cable median barrier€¦ · barrier, median barrier construction in marysville, and ongoing...

A report requested by the Governorof the state of Washington

Cable Median BarrierReassessment and Recommendations UpdateOctober 2009

Paula HammondSecretary of Transportation

John R. BatisteChief, Washington State Patrol

Under 23 United States Code Section 409, this data cannot be used in discovery or as evidence at trial in any action for damages against the WSDOT or any jurisdictions involved in the data.

Federal law 23 United States Code Section 409 governs use of this data. Under this law, data maintained for purposes of evaluating potential highway safety enhancements: “…shall not be subject to discovery or admitted into evidence in a federal or state court proceeding or considered for other purposes in any action for damages arising from any occurrence at a location mentioned or addressed in such reports, surveys, schedules, lists, or data.” [Emphasis added.]

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October 30, 2009 The Honorable Christine O. Gregoire Governor, State of Washington Legislative Building P.O. Box 40002 Olympia, WA 98504-0002 The Honorable Mary Margaret Haugen Chair, Senate Transportation Committee PO Box 49410 Olympia, WA 98504-0410

The Honorable Judy Clibborn Chair, House Transportation Committee PO Box 40600 Olympia, WA 98504-0600

Dear Governor Gregoire, and Chairs Haugen and Clibborn, Attached you will find the 2009 Cable Median Barrier Reassessment and Recommendations report. This edition fulfills a commitment from former WSDOT Secretary Doug McDonald and Washington State Patrol Chief John Batiste to provide annual cable barrier performance reports for two years following the independent review and recommendations made by Dr. Malcolm Ray in 2007. We will continue to monitor and assess the performance of this and other barrier systems used in Washington. Further reporting will occur in the department’s Gray Notebook. As you know, WSDOT and WSP are partners in highway safety. We are encouraged by Washington’s downward trend in traffic fatalities and the lowest number of traffic-related deaths since 1955. Enforcement, education and engineering solutions, such as cable median barrier, all play a role in reaching our goal of zero traffic-related fatalities and serious injuries by 2030. The 2009 update confirms that cable median barrier is an effective strategy for reducing cross-median collisions and saving lives. Our key findings from this year’s update include: • A 58% reduction in fatal and serious injury rates for all collisions in or across the median • For cross-median collisions only, there is a 65% reduction in collision rates for all injury severities • No cross-median collisions have occurred in the Marysville area since February 2007 WSDOT continues to monitor new developments in cable barrier systems and support research efforts related to barrier heights and motorcycle collision factors. We will update our cable barrier design guidance to incorporate new developments with cable barrier as appropriate. My staff will be pleased to answer your questions or provide more information. Sincerely,

Paula J. Hammond, PE Secretary of Transportation cc: House and Senate transportation committee members Washington State Transportation Commission

Chief John Batiste, Washington State Patrol

Cable Median Barrier - 1WSDOT/WSP

Table of contents:

Executive Summary

Chapter 1: Cable median barrier trends and performance ............................................ page 7

• WSDOT is reducing fatality rates by reducing crossover collisions

• Whatisincludedinthe2009analysisofmediancollisions?

• Adjustmentsandcorrectionsmadetorecordsinthe2008report

• 181milesofcablebarrierhavebeenplacedonWashington’shighways

• High-severitycollisionscontinuetodecline

• Wedidseeanoverallincreaseinmediancollisionswiththe installations of barriers

• Despiteanoverallincrease,fatalityandserious-injurycollision rateshavedropped58percent

• We’veseena61percentdecreaseinannualcross-mediancollisions

• Comparisonofbarriersystemscommonlyusedinhighwaymedians

• Containingvehiclesinthemedianresultsinfewermulti-vehiclecollisions

• ComparisonofCableBarrierandConcreteBarrierPerformance

• Cablebarrierstopsmorevehiclesinthemedianthanconcretebarrier

• High-tensioncablebarriersystemsareapproachingtheeffectiveness ofconcretebarrierinreducingcross-mediancollisions.

• Cablebarrieriseffectiveinreducingrollovercollisionsinthemedian

• Seriousandfatalinjurycollisionsin2008involvingcablebarriers

• Summaryoffatalmedianandcross-mediancollisionsin2008

• Summaryofserious-injurymedianandcross-mediancollisionsin2008

• WSDOT’sevaluationofmotorcyclecollisionswithcablebarrier

• Collisionsinvolvingmotorcyclesandcablebarrier

• Motorcyclecollisionresearchcontinues

Chapter 2: Cable barrier policy and update of WSDOT actions .................................... page 19

• PolicyRecommendations

• ResearchRecommendations

Chapter 3: Updates to median barrier on I-5 in Marysville ............................................ page 25

• ImplementingrecommendationstomodifytheI-5median barriersysteminMarysville

• Howwillthenewmedianbarriersystemhelptoreducecrossovercollisions?

• FederalstimulusfundingbroadenedthescopeoftheMarysvillebarrierproject

• WhathashappenedonI-5inMarysvillesincethelastreport?

2 - Cable Median Barrier WSDOT/WSP

Chapter 4: Next Steps ........................................................................................................ page 27

• Futureplannedinstallations

• Wewillconsidernewdevelopmentsincablebarriertechnology for future designs and installations

• Cablebarrierisbeingtestedinnarrowmediansandinotherapplications

• Morestatesareusingcablebarriersystems

Appendix A: Cable Median Barrier Installation Status Map ............................................... page 29

Appendix B: Performance of cable median barrier installations ....................................... page 31


Executive summary

IntroductionAttheendof2008,theWashingtonStateDepartmentofTransportation(WSDOT)hadinstalledatotalof181milesofcablemedianbarrieronstatehighways,andhadanother9.6milesundercontractforinstallation.Ourreviewofanotheryear’scollisiondataandtrendsshowsthatcablemedianbarrierscontinuetobeaneffectivetoolforsavinglives.From2000to2008,thenumberoffatalandserious-injurycollisionswithinoracrossthemediandecreasedby58percent.

Thisreportfurtherupdatestheindependent,expertevaluationconductedbyDr.MalcolmRayofWashington’scablemedianbarrierprogram,whichGovernorGregoiredirectedin2007followingahigher-than-averagenumberofcrossovercollisionsonInterstate5nearMarysville.TheresultsandrecommendationsfromDr.Ray’sreviewwerepublishedinJune2007,“CableMedianBarrier,ReassessmentandRecommendation.”Withanotheryearofcollisiondataforcablemedianbarriers,WSDOTpublishedanupdatetothe2007reportinSeptember2008(”CableMedianBarrier,ReassessmentandRecommendationsUpdate”).PreviousreportscanbefoundonWSDOT’sWebsite at www.wsdot.wa.gov/Projects/CableBarrier

The2009updateprovidesanoverviewofthechangesthathaveoccurredsinceourlastreport,includingcollisiontrendsandcablebarrierperformance,cross-mediancollisionsin2008,motorcyclecollisionsinvolvingcablebarrier,medianbarrierconstructioninMarysville,andongoingresearchandadvancementsincablebarriertechnology.

Cable median barrier trends and performanceTraffic fatality rates in Washington continue to decline, even as traffic volumes increase

From1990to2008vehiclemilestraveledhasincreasedby29percentandyet,wesawthehighestsingle-yearreductioninfatalandseriousinjurycollisionsonstatehighwayssince1990.In1990therewere2,491fatalandseriousinjurycollisionsonstatehighwayscomparedto1,024collisionsreportedin2008,areductionofnearly59percent.Cablemedianbarriersareoneoftheengineeringstrategiesthathavehelpedusachievethisoverallreduction.

In areas where cable barrier has been installed there has been a 61 percent reduction in the number of cross-median collisions annually

Priortocablebarrierinstallation,therewere54.8cross-medianincidentsperyearinthestudysegments.Thatnumberwasreducedto21.6incidentsperyear.

Cable barrier stops more vehicles in the median than concrete barrier

Keepingavehicleinthemedian,onceithaslefttheroadway,reducestheriskofitcollidingwithothervehicles.Inour2007report,wefoundthat10percentofthevehiclesstrikingcablebarrierwereredirectedbackingintotrafficlanes.Withtheadditionof2008data,wefindthatthepercentageisnow16percent.Thepercentageisstillwellbelowwhatwefindwithconcretemedianbarriers.Inouranalysis,79percentofvehiclesarecontainedinthemedianwithcablebarrier,comparedto34percentforconcretemedianbarrier.

Median and cross-median fataland serious-injury collisions

0

30

25

20

15

10

5

00 01 02 03 04 05 06 07 08

Source: WSDOT Transportation Data Of�ce and Headquarters Design Of�ce

Cross-median

Median

Year

Fatal and serious injury collisions

Figure 0.1


High-tension cable barrier systems are approaching the effectiveness of concrete barrier in reducing cross-median collisions

Ananalysisof58milesofconcretemedianbarrierrevealsthat2.2percentofthecollisionswithconcretebarrierresultedinvehiclestravelingoverorthroughthebarrierandreachedtheopposingtrafficlanescomparedwith3.7percentforhigh-tensioncablebarrierand6.0percentforlow-tensioncablebarrier.

Serious and fatal injury collisions involving cable barriers

Whilebarriersareintendedtoreducetheoverallseverityofcollisions,thereisalwaysariskofinjurywhenvehiclesleavetheroadway.Roadsidebarriers,seatbelts,drivingtacticsandstrategies,andvehiclemaintenanceallplayaroleintheoutcomeofanincident.In2008,thereweresevencollisionsreportedinoracrossthemedianthatresultedineightfatalitieswherecablemedianbarrierisinstalled.Thereweresixcollisionsin2008inoracrossthemedianwhereseriousinjuriesresulted.Speed,alcohol,inattentionandsleepydriverswerecommonbehaviorfactorsintheseevents.Seechapter1formoredetails.

WSDOT’s evaluation of motorcycle collisions with cable barrier

WSDOThasreviewedcollisionsinvolvingmotorcycleshittingmedianbarrier.Wehavefoundnosignificantdifferenceininjuryseverityregardlessofwhattypeofmedianbarriermotorcyclistsstruck.Throughtheendof2008,therehavebeensevencollisionsinvolvingmotorcyclesandcablemedianbarrierinWashingtonstate.Priorto2008wehadnotexperiencedanyfatalitiesresultingfrommotorcyclecollisionswithcablebarrier.Threeofthefatalcollisionsin2008weremotorcyclistsstrikingcablebarriers.Interactionbetweenthebarriersystemandtheriderwasvastlydifferentineachofthesecollisions.Seechapter1formoredetails.

WSDOTproposedanationalresearchproject,whichbeganin2009,toidentifycharacteristicsinvolvedinseriousinjuryandfatalcollisionsinvolvingmotorcyclesandtrafficbarriers.Resultsofthisresearchshouldbeavailablein2012.

Cable barrier and policy update of WSDOT actionsWashington’spolicyforcablemedianbarrierusagehasbeenevolvingsince1995whenWSDOT’sDesignManualfirstpresentedguidanceonuseofcablebarrierinhighwaymedians.Ourguidanceisexpectedtocontinuethisevolutionascablebarriersystemsevolveandmoreislearnedaboutcablebarrierplacementandperformance.InthisreportweprovidefurtherupdatestotherecommendationsmadebyDr.Ray,firstreportedin2007andupdatedin2008.Theseincluderecommendationson:

• installationandplacementofbarriers• fieldinspectionsofbarrierconnections• usingcrashhistoryasabasisforinstallingbarrier• researchefforts

TheManualonAssessingSafetyHardware(MASH)hasbeenadoptedbytheAmericanAssociationofStateHighwayandTransportationOfficials(AASHTO).Thismanualprovidesupdatedguidanceonuniformcrashtestingcriteria.Thetestingrequirementsforcablebarrieraremorestringentthantheyhaveeverbeen.

Modifying the median barrier on I-5 in MarysvilleTheJune2007CableMedianBarrierreportnotedahigher-than-averagenumberofcrossovercollisionsonI-5inMarysville.Asaresult,Dr.RayrecommendedinstallingconcretemedianbarrierandwideningtheshoulderalongnorthboundI-5inMarysvilletoprovidethehighestlevelofprotectionagainstcrossovercollisions.


Therehaven’tbeenanycross-mediancollisionsinthesegmentsinceFebruary2007.

Followingtheserecommendations,inDecember2007Gov.Gregoireallocated$26.9milliontoreplacetheexistinglow-tensioncablemedianbarrierwithconcretebarrieralong10milesofnorthboundI-5inMarysville.ThefundingwasapprovedbytheLegislatureinMarch2008,allowingWSDOTengineerstobegindesigningtheproject.

WeadvertisedtheMarysvillemedianbarrierprojectforcompetitivebidsinApril2009,andinJuneweawardedthecontracttoTri-StateConstruction,Inc.ConstructionbeganinlateJuly2009.Barrierinstallationisexpectedtobecompletebyspring2010.Totalprojectcompletionisexpectedinlate2010.Moreinformationisavailableat:www.wsdot.wa.gov/Projects/I5/MarysvilleMedianBarrier

More states using cable barrier systemsInpreparingtheJune2007cablebarrierreport,weconsultedotherstatesregardingtheiruseofcablemedianbarriersystems.Attheendof2006therewere14statesthathadnotinstalledanycablebarrier.Thatequatesto72percentofstates.Nowtwoyearslater,thereareonlyfourstatesthathavenocablebarrierinthemedians.Ninety-twopercentofthecountryhasadoptedcablebarrierforuseasamedianbarrier.SeeFigure4.2inchapter4.

Future Planned InstallationsThereare25milesofhighwaymedianidentifiedforcablebarriertreatmentwithprojectstobeadvertisedin2010.Whenalloftheplannedinstallationsarecomplete,weexpecttohave219milesofourhighwaymedianstreatedwithcablebarrier.Ourmorerecentinstallationshavebeenfour-cablebarriers,incontrasttothethree-cablebarriersthatcomprisemostofourexistinginventory.Cablebarriersystemshaveevolved,utilizingfourcablestoexpandtherangeofheightcoverage.Ahighertopcableandlowerbottomcablefurtherreducestheprobabilityofvehiclesgettingunderoroverthebarrier.


Chapter 1: CableMedianBarriertrendsandperformance

WSDOT is reducing fatality rates by reducing crossover collisionsWSDOTusesmedianbarrierstoreducethefrequencyandseverityofcollisionsinoracrossthemedian.Reducingthenumberofvehiclesreachingtheopposingtrafficlanesisoneoftheobjectivesofplacingbarrierinhighwaymedians.

In2008,approximatelyone-thirdofallfatalcollisionsonWashingtonhighwaysinvolvedvehicleseithercrossingthecenterline,orinthecaseofdividedhighways,crossingthemedianintoopposingtrafficlanes.WSDOTisworkingtoreduceseriousandfatalinjurycollisionsinWashington.Inpursuitofthisobjective,WSDOThastargetedmediancrossovercollisionsasoneofthestrategiestobringdowntheoverallnumberofseriousandfatalinjurycollisionsondividedhighways.In2002WSDOTbeganimplementingasystemwideapproachtofocusoncablemedianbarrierasameanstoreducecross-mediancollisions.Themajorityofthelocationsidentifiedforcross-medianprotectionhadexistingmedianswidthsof30to50feet.

Oureffortsaremakingadifference.Overthepast18years,thefatalityrateonallWashingtonpublicroads(state,cityandcounty)hasdecreased49percent,from1.85per100millionvehiclemilestraveled(VMT)in1990to0.94in2008.In2007,themostrecentlyavailablenationaldata,Washingtonranked9thlowestinthenation.ForWashingtonstatehighwaysonly,duringthissametimeperiod,fatalandseriousinjurycollisionshavedeclined59percent,from2,491collisionsin1990to1,024in2008,whilethestatehighwayVMTincreased29percent.Theyear2008representsthehighestreductionoffatalandseriousinjurycollisionsonstatehighwaysforasingleyearsince1990.Theseimprovementsareachievedthroughtheeffortsoflawenforcementagencies,emergencyresponse,engineering,drivereducation,andautomobilemanufacturers.Medianbarriersareoneoftheengineeringstrategiesthathavehelpedusachievethisoverallreduction.

What is included in the 2009 analysis of median collisions?Before and after comparisons:

Thisreportcomparesmediancollisionexperienceinafive-yearperiodbeforebarrierwasinstalledwiththecollisionexperienceaftermedianbarrierwasplaced.WSDOTanalyzedover3,100collisionsalong181milesofcablebarrierwithinstallationsstartingin1995,continuingthroughDecember2008.Collisionsoccurringduringconstructionofthecablebarrierarenotnormallyincluded,sincethetrafficcontrolusedduringconstructionpresentsuniquetrafficconditionsthatdonotofferafaircomparison.

Webelievethatcrossmediancollisionsinthe“before”periodoccurredmorefrequentlythanreportedinthisstudy.Wecaneasilyidentifycollisionswherethevehicle’sinitialpointofimpactwasacrossthemedian.Becausethestruc-tureofourcollisiondataidentifiesonlytheinitialpointofimpact,itdoesnotallowustoidentifythesequenceofeventsoccurringafterthatinitialimpact.Itdoesnotallowustoidentifycrossmedianeventssuchasasame-directionsideswipewhereavehicleisreboundedacrossthemedian,oreventswhereavehiclecrossedthemedianwithouthittinganything.

Togathermoreinformationaboutthesequenceofeventsinacollision,wehavetogobacktothetrooper’sreports.Inmanycases,thetrooper’sreportsarenolongeravailableforthattimeperiod.Evenwhenthetrooper’sreportsdoexist,thereisnoreliablemeanstodeterminewhichreportstoreview.Inanattempttoidentifyadditionalcross-medianeventswiththemostsevereinjuries,wehavereviewedtrooper’sreportsforfatalandserious-injurycollisionssince2000.

Figure 1.1

Traffic Fatality Rate in WashingtonCompared to National Average

0

1.0

2.0

3.0

4.0

3.5

2.5

1.5

.5

1980 1985 1990 1995 2000 2005

Provided by: WSDOT-Transportation Data Of�ce (TDO)Sources: US Fatalities/VMT: FARS Encyclopedia, WA Fatalities; FARS; State Hwy Fatalities: WSDOT-TDO; WA VMT: WSDOT TDO

Year

All Washington State Public Roads

Washington State Highways

United States(2008 not yet available)

Fatalities per 100 Million VMT, 1980-2008


Figure 1.2

Unreported collisions:

Thereareinstanceswheredriversdidnotreportacollision,anddroveawayafterstrikingthebarrier.Togainsomeinsightonthefrequencyofunreportedcollisions,wereviewedcablebarrierrepairrecordsfromourmaintenanceofficesduring2008.Ourreviewofrepairrecordsandacomparisonwithreportedcollisionsrevealsthattherearesubstantialnumbersofunreportedcollisionsinvolvingcablebarrier.Wefound569cablerepairrecords,comparedto478reportedcollisions.Wewereabletomatchabout65percent(368records)ofthe2008repairswithspecificcollisionreports.Fromthiscomparison,weestimatethat20to40percentofcollisionswithcablebarrierareunreported.Becauseseriousinjurycollisionsarenormallyreported,wepresumethatnoneoftheunreportedcollisionsinvolvedseriousinjury.

Comparison with other types of barriers:

Wealsocomparedperformanceofcablebarrier,beamguardrail,andconcretebarriersusedinthemedian.Weconductedasystem-widestudyandamoredetailedsegmentanalysisof58milesofconcretebarrierinstallationsasacomparisontothe181milesofcablebarrierinstallations.

Adjustments and corrections made to records in the 2008 reportAswereviewedthecollisionrecordswefoundthatafewrecords(15)presentedintheSeptember2008“CableMedianBarrierReassessmentandRecommendationsUpdate”reportrequiredsomeadjustmenttocorrectreportingissuessuchas:

• Recordsnotidentifiedinthe2008report.• Correctionsmadetoresolvereportingerrorsindirectionoftravel,or impactlocation.

• Moreinformationwasobtained.• Collisionrecordwiththewronghighwayidentifier.• Betterinformationonconstructionprojectdates.• Updatedinformationonconstructionprojectdates.• Collisionswerefoundtobeonundividedhighways.

181 miles of cable barrier have been placed on Washington’s highwaysBytheendof2008,therewere181milesofcablemedianbarrierinplaceandanother9.6mileswereundercontractforinstallation.Approximatelysixmilesofnewcablemedianbarrierwascompletedin2008.Someofthecablebarriermileagepresentedinthe2007and2008reportswasremovedduring2008.Aroadwaywideningprojecthasaddedlanesinthemedianandisplacingconcretebarrierbetweenopposingtravellanes.Thenarrowedmediandoesnotprovideadequatewidthforthedeflectioncharacteristicsofatypicalcablebarriersystem.Themaintenancerequirementsassociatedwithcablebarrierrepairswouldalsoplaceourmaintenancecrewsclosertotraffic.

Figure1.2providesayear-by-yearbreakdownofthe181milesofcablebarrierinstalledbetween2000and2008.

High-severity collisions continue to declineThefullmeasureofeffectivenesswithmedianbarriersistheoverallimpactonseriousandfatalinjurycollisions.Whilecross-mediancollisionsareanimportantcomponentinmedianbarrierperformance,engineersmustlookatallcollisionsinvolvingabarriersystemtofullyassessperformance.Between2000and2008thereisadramaticdeclineinfatalandserious-injurycollisionswithinoracrossthemedian.Figure1.3illustratesthenumberoffatalandserious-injurycollisionsoccurringwithinoracrossthemedianwherecablebarrierhasbeeninstalled.ThedeclineinseriousandfatalinjurycollisionscorrespondstotheincreaseinmilesofbarrierplacedasillustratedinFigure1.2.Figure1.3doesnotisolatecollision

Miles of Cable Median Barrier Installed by Year End

Installation of cable median barrierMiles

0

180

160

140120

100

80

60

40

20

180

200

00 01 02 03 04 05 06 07

Source: WSDOT Headquarters Design Of�ce

Year08


experiencebeforeandafterthecablebarrierwasplaced,itsimplypresentsthechangeincollisionexperiencethatwehaverealizedwithourmedianbarrierprogramovertime.Abefore/aftercomparisonispresentedlaterinthisreport.

Figure1.3’soveralldownwardtrendinfatalandseriousinjurymediancollisionsissignificantconsideringtheincreaseinmilestraveledfrom2000to2008.Figure1.4illustratestrafficvolumegrowthfrom2000through2008.

Withtheadditionofanotheryearofcollisiondata,wenotedthereductioninannualcross-mediancollisionsappearstobelessdramaticthanreportedin2008.Ascableinstallationsforlimited-accessfreewayswithmediansof50feetornarrowerarenearingcompletion,thereductionincollisionsthatcanbeexpectedbyinstallingbarrierhasbeenrealizedandislevelingoff.

We did see an overall increase in median collisions with the installations of barriers Onceabarrierhasbeenaddedtoamedian,errantvehiclesnolongerhavethefullwidthofthemediantorecoverwithoutstrikingthebarrierorotherobject.Consequently,reportablecollisionsinthemedianroutinelyincreaseaftertheinstallationofanybarriersystem.ThismeansthatWSDOTengineersconsiderthebalancebetweenthebenefitsofbarriersandtheirassociatedrisks.Inthestudysections,therewere228collisionsreportedannuallypriortobarrierplacementand594afterplacingcablemedianbarrier.Thatamountstoanincreaseof161percent.Figure1.5summarizesthisdata.

Despite an increase in overall collisions, fatality and serious-injury collision rates have dropped 58 percentExpressingcollisionsasarateallowsustocompareperformanceonsegmentswithdifferentlengthsandtrafficvolumes.Thisreportpresentsinformationoncollisionrates,expressingthenumberofcollisionsforeach100millionvehiclemilesoftravel(MVMT).Presentingannualcollisionsisanothermeanstopresentthedatausingacommonreferencepoint,althoughitdoesnotaccountfortrafficgrowthovertime,

Theoverallcollisionratejumpedfrom7.85collisionsper100MVMTto15.99per100MVMTaftercablebarrierwasplaced.Despitetheoverallincreaseincollisions,weareachievingourobjectiveofreducingseriousandfatalinjurycollisions.Therateofserious-injurycollisionswasreducedby64percentandtherateoffatalcollisionswasreducedby44percent.CollisionratedataispresentedinFigure1.5.

Ifchangesintrafficvolumearenotfactoredintotheanalysis,westillseea48percentreductioninannualfatalandserious-injurycollisionsaftercablemedianbarrierwasplaced.Therewere24.8fatalandseriousinjurycollisionsperyearpriortoinstallationofbarrierand13.0after.

Figure 1.5Collision Rate Data “Before” and “After” Cable Barrier Installation

Before

After

Percent change

Annual median collisions 228 594 +161%

Median collision rate (per 100 million vehicle miles of travel)

7.85 15.99 +104%

Annual serious-injury median collisions 16.8 7.0 -59%

Annual fatal median collisions 8.0 6.0 -25%

Serious-injury median collision rate (per 100 million vehicle miles of travel)

0.58 0.21 -64%

Fatal median collision rate (per 100 million vehicle miles of travel)

0.27 0.15 -44%

Median and cross-median fataland serious-injury collisions

0

30

25

20

15

10

5

00 01 02 03 04 05 06 07 08

Source: WSDOT Transportation Data Of�ce and Headquarters Design Of�ce

Cross-median

Median

Year

Fatal and serious injury collisions

Figure 1.3

Vehicle Miles Traveled (VMT)Within the Segments Where Cable Median Barriers Were Installed*

0

10

20

30

40

00 01 02 03 04 05 06 07 08

*181 miles of cable barriers were installed by the end of 2008.

Year

Trend 2000-2007 (VMT in millions)

Figure 1.4


We’ve seen a 61 percent decrease in annual cross-median collisionsFigure1.6illustratescablemedianbarrier’seffectoncross-mediancollisions.Priortocablebarrierinstallation,therewere54.8cross-medianincidentsperyearinthestudysegments.Thatnumberwasreducedto21.6incidentsperyearaftercablebarrierwasinstalled.Thenumberofannualcross-medianfatalandseriousinjurycollisionswasreduced57percent,droppingfrom13.4to5.8.

Figure 1.6

Cross-Median Collisions

Before

After

Percent change

Annual cross-median incidents 54.8 21.6 -61%

Cross-median collision rate (per 100 million vehicle miles of travel)

1.88 0.66 -65%

Annual serious-injury cross-median collisions 8.6 2.3 -73%

Annual fatal cross-median collision 4.8 3.5 -28%

WSDOT’scablemedianbarrierprogrambeganwithlow-tension(generic)barri-ers.Overtime,cablebarriersystemshaveevolvedtooffermultiplehigh-tensionsystemsavailablefromseveralmanufacturers.High-tensionsystemshavedomi-natedWashington’scablemedianbarrierinstallationssince2004.Attheendof2008,therewere41milesofgenericlow-tensionbarrierinplaceand140milesofhigh-tensionbarrier.Washingtonhasnotinstalledanygenericlow-tensioncablebarriersince2005.Althoughlow-tensioncablebarriersareeffectiveandcontinuetobeusedacrossthecountry,WSDOThasfoundhigh-tensioncablebarriersystemstobecompetitivelypricedandeasiertomaintain.Fornew-installations,theWSDOTDesignManualspecifieshigh-tensioncablebarrier,nolongerpresentingthegenericlow-tensioncablebarrierasanoption.

Thecollisionexperiencewiththesedifferentsystemsallowsustocompareperformanceofthelow-tensionandhigh-tensioncablebarriersystems.Adi-rectcomparisonofexperienceinWashingtoniscomplicatedbysomepolicychanges.Aboutthesametimethathigh-tensioncablebarriersbeganappear-inginWashington,wealsoimplementedchangesinourplacementguidance.Consequently,itisdifficulttodrawabsoluteconclusionsregardingwhetherthehigh-tensionsystemsareactuallyperformingbetterorwhetherchangesincablebarrierplacementarehavingasignificantinfluenceonthereductionincross-me-diancollisions.Althoughweattemptedtoseparatetheshifttohightensionfromthepolicychange,wefoundthemtobetoocloselylinkedtoisolatetheeffects.

Withconsiderationofthejointeffectsofsystemchangeandpolicychange,wefoundthatacomparisonoflow-tensionandhigh-tensioncablebarriersystemsindicateahigherincidenceofvehiclesbeingredirectedbackintotraffic

Figure 1.7

Comparing low- and high-tension cable median barriers system performance

Barrier type

Barrier performance

Reported collisions

Not stated

No injury

Possible injury

Evident injury

Serious injury

Fatal

Low-tension Contained in median 742 (85.9%) 16 (1.9%) 598 (69.2%) 68 (7.9%) 50 (5.8%) 8 (0.9%) 2 (0.2%)

Redirected 70 (8.1%) 3 (0.3%) 58 (6.7%) 4 (0.5%) 4 (0.5%) 1 (0.1%) 0

Cross-median 52 (6.0%) 0 17 (2.0%) 10 (1.2%) 13 (1.5%) 6 (0.7%) 6 (0.7%)

High-tension Contained in median 560 (71.5%) 3 (0.4%) 459 (58.6%) 54 (6.9%) 37 (4.7%) 4 (0.5%) 3 (0.4%)

Redirected 194 (24.8%) 4 (0.5%) 150 (19.2%) 26 (3.3%) 11 (1.4%) 2 (0.3%) 1 (0.1%)

Cross-median 29 (3.7%) 0 16 (2.0%) 3 (0.4%) 3 (0.4%) 2 (0.3%) 5 (0.6%)


laneswithhigh-tensioncablebarrier(seeFigure1.7).Thedatashowthatthepercentageofcross-mediancollisionsislowerwiththehigh-tensioncablebarrierinstallations.

Low-tension cable barrier installation

CablesaremountedwithJ-boltstopostsplaced16feetapart,andsecuredtoconcreteanchorsburiedevery2,000feet.Attheanchors,thecablesareattachedtospringsandtightened.Thespringsaredesignedtoexpandandcontractwithtemperaturechanges.Thecablestightenandflexastheybringthevehicletoastopwithalowlikelihoodforredirectingitbackintotrafficorallowingittocrossthemedian.Instandardcrashtests,atover60mphandanimpactangleof25degrees,thecablesflexasmuchas12feet.

Low-tension cable barrier anchor

Ifavehiclehitstheendofthebarrierwherethecablesareanchored,thecablesaredesignedtoreleasefromtheanchor,lesseningtheforceofimpacttransferredtopeopleinsidethevehicle.Withoutthereleasemechanism,cableanchorswerefoundtoincreasethefrequencyofrollovers,andhighernumbersofinjuries.

High-tension cable barrier installation

AfterWSDOTbeganinstallingcablebarrierinthemedian,privatemanufacturingcompaniesenteredthemarketwithhigh-tensionsystemswithreduceddeflection.Likelow-tensionsystems,high-tensioncablemedianbarrierscurrentlyinplaceonWashingtonhighwaysconsistofthreestrandsofsteelcable-mountedonposts.Ourhigh-tensionbarriersstringthecablesthroughslotsinthemiddleoftheposts,typicallyspaced16feetapart.Withhigh-tensionssystems,thecablesdon’tflexlaterallyasfarastheirlower-tensionpredecessors,sotheycanbeusedinnarrowerspaces.Whenavehiclestrikesthehigh-tensioncablemedianbarrier,thepostsaredesignedtobenddown,allowingthecablestoslipoutoftheirslotstocatchthevehicle.Thehighercabletensionalsoincreasesthelikelihoodthatthecablewillremainataserviceableheightpriortorepairifacoupleofthepostswereknockeddown.

High-tension cable barrier anchor

Theanchorsforthistypeofsystemhavebeenplacedasmuchasthreemilesapart,althoughobstaclessuchasbridges,otherbarriersystems,orhighwayhardwareoftenmakethatlengthimpractical.Eachcableisattachedtoitsownanchorpostandisdesignedtobreakfreewhenstruckbyavehicle.

Comparison of barrier systems commonly used in highway mediansWSDOTusesbeamguardrail,concretebarrier,andcablebarrierstoreducecross-mediancollisionsandbringdownthenumberofseriousandfatalinjurycollisions.Longerinstallationsaretypicallyconcreteorcablebarrierratherthanbeamguardrail.

Figure1.8presentsacomparisonofinjuryseverityforthethreebarriersystemsmostcommonlyusedinthemediansofWashington’shighways.Weanalyzeddataforallcollisionswithcablebarrierthroughtheendof2008andcollisionswithbeamguardrailandconcretebarrierfrom2002through2008.Thesedatashowthat20percentofcollisionsinvolvingcablemedianbarrierresultininjuryordeath.Beamguardrailcollisionsresultininjuryordeath37percentofthetime,andforconcretebarriersit’s38percent.

Containing vehicles in the median results in fewer multi-vehicle collisions Ourupdatedanalysisresultedinverysimilarperformancecomparisonswiththe2007and2008cablebarrierreports.Theincreasedmileageofhightension


systemsandacorrespondingincreaseinoverallnumberofcollisionsreflectsanincreaseinthenumberofcrossmediancollisions,andfatalcollisions.

Figure1.9illustratesthatcablebarriercollisionsinvolvemultiplevehicles17percentofthetime,whilethatnumberincreasesto32percentwithconcretebarrierand36percentwithbeamguardrail.

Figure1.10illustratesthenumberofinjuriespercollisioneventwiththevariousbarriertypes,withsingle-vehicleandmulti-vehiclecollisions.Cablebarriercollisionsresultinlowernumbersofinjuriespercollisionthanotherbarriertypes.

Comparison of Cable Barrier and Concrete Barrier PerformanceWSDOTengineerstookacloserlookat58milesofconcretebarrierinstallationsandcomparedthemto181milesofcablebarrier.Theseconcretebarriersegmentswereselectedbecausetheirsitecharacteristicsweresimilarwithhighwaylocationswherecablemedianbarrierhadbeenplaced.

Cable barrier stops more vehicles in the median than concrete barrier Itisdesirabletokeepvehiclesinthemedianoncetheyhavelefttheroadway.Vehiclesthatcrossthemedianorareredirectedbackintotraffichaveagreaterprobabilityofinvolvingadditionalvehicleswhichlikelyresultinhighernumbersofinjuries.

Inour2007report,wefoundthat10percentofthevehiclesstrikingcablebarrierwereredirectedbackintotrafficlanes.Withtheadditionof2007and2008collisiondata,wefindthatthepercentageofredirectedvehiclesisnow16percent.Inspiteofthatincrease,thepercentageisstillwellbelowwhatwefindwithconcretemedianbarriers.Ouranalysisindicatesthat79percentofthecablebarriercollisionsarecontainedinthemediancomparedwith34percentforconcretemedianbarrier(Figure1.11).Thehighpercentageofvehiclesredirectedbyconcretebarrierisinfluencedbythefactthatconcretebarriersaremorefrequentlyusedinnarrowermedians,wheretheimpactingvehicledoesnothavetotravelasfartore-enterthelanes.

Figure 1.8

Barrier Systems Commonly Used in the Median

Barrier type

Reported collisions

Not stated

No injury

Possible injury

Evident injury

Serious injury

Fatal

Cable barrier 1,647 26 (1.6%) 1298 (78.8%) 165 (10.0%) 118 (7.2%) 23 (1.4%) 17 (1.0%)

Beam guardrail 2,979 59 (2.0%) 1,828 (61.4%) 654 (22.0%) 361 (12.1%) 56 (1.9%) 21 (0.7%)

Concrete barrier 9,708 183 (1.9%) 5,788 (59.6%) 2,394 (24.7%) 1155 (11.9%) 148 (1.5%) 40 (0.4%)

Total 14,334 268 (1.9%) 8,914 (62.2%) 3,213 (22.4%) 1,634 (11.4%) 227 (1.6%) 78 (0.5%)

Cable barrier Concrete barrier

100

90

80

70

60

50

40

30

20

10

0Beam guardrail

Single vehicle

Multiple vehicle

Figure 1.9

Percentage of single- and multi-vehicle collisions with barrier types

2002-2008*

Percent

*Timeperiodanalyzedforconcretebarrierandbeamguardrailcollisions.

Collisions Cable barrier Concrete barrier Beam guardrail

Single-vehicle collisions 0.17 0.43 0.49

Multiple-vehicle collisions 0.93 0.66 0.67

All collisions 0.30 0.51 0.56

Figure 1.10

Number of injuries per collision


Figure 1.12

Concrete barrier shows a slightly lower percentage of cross-median collisions

Low-tension cable barrier (41 miles) 1995-2008

High-tension cable barrier (150* miles) 2004-2008

Concrete barrier (58 miles) 2002-2008

Cross-median incidents 52 (6.0%) 29 (3.7%) 28 (2.2%)

Cross-median rate (per 100 million vehicle miles of travel)

0.67 0.64 0.25

Fatal crashes where barrier was impacted

8 (0.9%) 9 (1.1%) 7 (0.8%)

Deaths from collisions where barrier was impacted

12 11 10

Fatal crash rate (per 100 million vehicle miles of travel)

0.10 0.20 0.06

*Marysvillesectionhasdualrunsofbarrier.SouthboundcollisionsafterFebruary2007areattributedtohigh-tensioncablebarrier.Allothersarelow-tension.

High-tension cable barrier systems are approaching the effectiveness of concrete barrier in reducing cross-median collisions.

Addingmorecollisionstothedatayieldedresultsthatareverysimilartowhatwasreportedlastyear.

• 97.8percentofthecollisionswithconcretebarrierdidnotreachtheopposinglanes

• 96.3percentofthecollisionswithhigh-tensioncabledidnotreachtheopposinglanes

• 94.0percentofcollisionswithlow-tensioncablebarrierdidnotreachtheopposinglanes

Ananalysisof58milesofconcretemedianbarrierrevealsthat2.2percentofthecollisionswithconcretebarrierresultedinvehiclestravelingoverorthroughthebarrierandreachedtheopposingtrafficlanescomparedwith3.7percentforhightensioncablebarrierand6.0percentforlow-tensioncablebarrier.

Barrier performance Cable barrier Concrete barrier

Contained in median* 1,302 (79.1%) 441 (34.0%)

Redirected** 264 (16.0%) 828 (63.8%)

Cross-median*** 81 (4.9%) 28 (2.2%)

Total 1,647 1,297* Contained in median: The vehicle hit the barrier and did not re-enter any lanes of traffic.

** Redirected: The vehicle hit the barrier and rebounded into the lanes of traffic.

*** Cross-median: The vehicle hit the barrier, went across the median, and entered the opposing lanes. To be conservative, WSDOT considered any incident as a cross-median incident whether or not there was a collision with opposing traffic. In our analysis, there were 32 cross-median incidents involving cable barrier where there was not a collision with opposing traffic: 56 percent of the total.

Figure 1.11

Comparison of cable barrier and concrete barrier performance


Cable barrier is effective in reducing rollover collisions in the median Inrollovercollisions,vehicleoccupantsaresubjectedtoawiderrangeofforcesandmorefrequentimpactswithvehiclecomponents,resultinginmoresevereinjuries,particularlyathigherspeedsandwithunrestrainedoccupants.Figure1.13illustratesanoverallreductionof28percentforallrollovercollisionsinthemedian.Forserious-injurycollisions,thereductionis67percent,anda20percentreductionwasfoundforfatalcollisions.

Figure 1.13

Cable barrier is effective in reducing rollover collisions in the median

Before After Percent change

Annual median rollover collisions 84.0 60.7 -28%

Median rollover collision rate (per 100 million vehicle miles of travel)

2.99 1.62 -46%

Annual serious-injury median rollover collisions 8.6 2.7 -69%

Annual fatal median rollover collisions 2.8 2.2 -20% Serious and fatal injury collisions in 2008 involving cable barriersWhiletheplacementofcableandotherbarriersisintendedtoreducetheoverallseverityofcollisions,thereisalwaysariskofinjurywhenvehiclesleavetheroadway.Roadsidebarriers,vehiclerestraintsystems,drivingtac-ticsandstrategies,andvehiclemaintenancepractices,allplayaroleintheoutcomeofanincident.

Notallcross-mediancollisionsresultedinafatality,howeverin2008,thereweresevencollisionsreportedinoracrossthemedianthatresultedineightfatalitieswherecablemedianbarrierisinstalled.Allofthesecollisionsinvolvedthecablemedianbarrier.Thosecollisionsandseriousinjurycross-mediancollisionsaresummarizedbelow:

Summary of fatal median and cross-median collisions in 2008SR 512, Milepost 7, Puyallup - March 13, 2008:Thedriverofawestboundtruckandsemi-trailerwasreachingforacompactdiscfromthefloorofthetruckwhenhedriftedintothemedianandoverthecablebarrier.Thetruckcontinuedacrosstheeastboundlanes,wherethetrailerwasstruckbyasecondvehicle,shearingtheroofoffthesecondvehicle.Athirdvehiclealsostruckthetrailer.Thedriverofthesecondvehiclediedatthescene.Driverinattentionwasafactorinthiscollision.

SR 16, Milepost 15, - May 23, 2008:ThedriverofaFordExpeditionwaswestbound,anddriftedofftheroadtotheright.Thedriverthenover-correctedandcrossedbothlanesandenteredthemedianwhereitstruckthecablebarrier.TheSUVwentoverthecablebarrier,rolledseveraltimesandcametorestonitsside,blockingbotheastboundlanes.Thedriverdiedatthescene.Speedanddriverinattentionwerefactorsinthiscollision.

I-5, Milepost 88, Grand Mound - October 3, 2008: Thedriverofasouthboundtruckandsemi-trailerobservedslowingtrafficandmadealanechangetotheright.AsouthboundSubaruLegacywasintherightlanewhenthetruckmovedover.TheSubaruturnedtotheleftandcrossedbothsouthboundlanesandenteredthemedian.TheSubaruwentunderthecablebarrierandcrossedintothenorthboundlaneswhereitstruckatruckand


semi-trailerhead-on.ThedriverandfrontseatoccupantintheSubarudiedatthescene.

SR 512, Milepost 9, Puyallup - November 3, 2008: ThedriverofaneastboundAcuralefttheroadwaytotheleft,enteredthemedian,struckthecablebarrier,androdeoverthetop.TheAcuracrossedthemedian,enteredthewestboundlanesandstruckaToyotapickup.Bothvehiclesthenstruckasemi-truckandtrailer.ThedriverofAcuradiedatthescene.

Threeotherfatalcollisionsarelistedinthesummaryofmotorcyclecollisions.

Summary of serious-injury median and cross-median collisions in 2008

I-5, Milepost 114, Nisqually - January 11, 2008:AToyotapickupwastravelingsouthbound(wrongway)inthenorthboundlanesandsideswipedanorthboundFordpickup.TheToyotacontinuedsouthboundandstrucknorthboundHondaCivicnearlyheadon.TheToyotacametorestinthemedianonthecablebarrier.ThedriveroftheHondasufferedabrokenleg.Alcoholwasafactorinthiscollision.

I-5, Milepost 22, Vancouver- March 20, 2008: Twovehiclescollidedinthenorthboundlanes.Onevehicleswervedleftintothemedianandwasrestrainedbythecablebarrier.Theothervehiclelostcontrol,lefttheroadtotherightandstruckatree.Thedriverofthevehiclestrikingthetreesufferedabrokenankle,brokencollarbone,andchestandneckpain.Inattentionanddrowsydrivingwerefactorsinthiscollision.

I-90, Milepost 298, East of Spokane - March 30, 2008: AwestboundChevysedanlostcontrolontheice,slidintothemedian,androlledover.TheChevycametorestonthecablebarrier.Thedriversufferedheadinjuries.Speedwasafactorinthiscollision.

US 12, Milepost 15, Montesano to Elma - April 20, 2008: An eastbound ChevyvanstrucktherearofaneastboundOldsmobile.TheOldsmobilespuntotheright,strucktheguardrail,rotatedandre-enteredthelanes,whereitwasstruckbyaKenworthtractor/trailercombination.TheOldsmobilewaspushedbacktotherightshoulderstrikingtheguardrailasecondtime.TheChevyvanlefttheroadwaytotheleft,struckthecablebarrier,veeredtotherightcrossingthelanesandstrucktheguardrailontherightshoulder.Thevancontinuedapproximately1/4mile,wherethedriverfledthescene.Thevanhadbeenstolen.ThedriveroftheOldsmobilesufferedinternalinjuries.Speedwasafactorinthiscollision.

SR 3, Milepost 52, Silverdale - June 4, 2008: AnorthboundIsuzuSUVlefttheroadwaytotheleft,struckthecablebarrier,androlledmultipletimes.TheSUVcametorestinthemedian.Thedriversufferedheadandneckinjuries.Alcoholandspeedwerefactorsinthiscollision.

182, Milepost 13, Pasco - October 1, 2008: AneastboundMercurysedan,lostcontrolanddriftedtotheright,strikingthereartrailertiresofaPeterbuilttractor/trailercombination.TheMercurybouncedoff,wentthroughthecablemedianbarrier,acrossthewestboundlanes,andcametorestonthewestboundshoulder.ThedriveroftheMercurysufferedinjuriestothehead,back,neck,andwrist.Alcoholwasafactorinthiscollision.


WSDOT’s evaluation of motorcycle collisions with cable barrierSomemotorcyclistshaveexpressedconcernthatcablebarriersystemspresentahighriskforseverelacerations,orevendismembermentfromcontactwiththecables.Whilemotorcyclistsareatgreaterriskofinjuryinacollisionthanoccupantsinmostothervehicles,thereislittleevidencethatthesetypesofinjuriesareoccurring.WSDOThasreviewedcollisionsinvolvingmotorcycleshittingmedianbarrier.Wehavefoundnosignificantdifferenceininjuryseverityregardlessofwhattypeofmedianbarriermotorcyclistsstruck.

Collisions involving motorcycles and cable barrierThroughtheendof2008,therehavebeensevencollisionsinvolvingmotorcyclesandcablemedianbarrierinWashingtonState.Priorto2008wehadnotexperiencedanyfatalitiesresultingfrommotorcyclecollisionswithcablebarrier.Unfortunatelythattrendchangeddramatically,withthreefatalcollisionsin2008.ItisimportanttonotethatconcernaboutseverelacerationsordismembermentresultingfromcontactwiththecableshasnotbeenanissueinWashington.Contactwithpavementwasthesourceofinjuryintwoofthe2008collisions.Contactwiththepostwasthemethodofinjuryinthethirdevent.

I-90, Milepost 184, Moses Lake – Oct. 26, 2008: AninexperienceddriverwasenteringI-90westboundatMP184eastofMosesLake,whenheleftthepavedon-ramptotheleft,crossedthroughagravelareabetweentherampandtheinterstate,crossedtheinterstatetrafficlanes,enteredthemedian,andstruckthecablebarrier.Thedriverwasuprightonthemotorcyclewhenitstruckthebarrier,wassubsequentlyejected,strikingthegroundwithhishead.Thedriverwasdeadatthescenefromabrokenneck.Driverinattentionwasafactorinthiscollision.

SR 99, Milepost 25, Seattle - Aug. 24, 2008:AnorthboundmotorcycleonSR99betweenTukwilaandSeattlewastravelingathighspeed,lostcontrol,andoverturnedinthelane.Witnessesreportedthedriverwasdoingwheeliespriortothecrash.Thedriverseparatedfromthemotorcycleandstruckacablebarrierpostwithhisback.Thedriverwasdeadatthescenefromspinalinjuries.Speedwasafactorinthiscollision.

SR 512, Milepost 10, Puyallup - June 27, 2008: AwestboundmotorcycleonSR512wasobservedtravelingathighspeed,passingvehiclesonbothshoulders.Thedriverlostcontrol,overturninginthelanes,andslidintothecablebarrier.Thedriversufferedbrokenbonesandabrokenneckresultingfrompavementcontactandwaspronounceddeadatthescene.Theinvestigatingofficerreportedthatthedrivercametorestagainstapostofthebarriersystem.Thedriverwasfoundtobeundertheinfluenceofalcohol.Alcoholwasafactorinthiscollision.

Motorcycle collision research continuesAsmentionedinthe2008cablebarrierreport,aWSDOTproposedresearchprojecttitled“IdentificationofFactorsRelatedtoSeriousInjuriesinCrashesofMotorcyclistsintoTrafficBarriers,”wasselectedforfundingaspartoftheNationalCooperativeHighwayResearchProgram(NCHRP).Thisstudybeganin2009andtheresultsshouldbeavailablein2012.

Thisstudywillidentifycharacteristicsinvolvedinserious-injuryandfatalcollisionsinvolvingmotorcyclesandtrafficbarriers.Theresearchwill


investigatecharacteristicsrelatedtothedriversinvolved,thecollisiontypes,thebarriertypes,theroadwaygeometryandconditions,thevehicletypes,andtheenvironmentalconditions.Thestudywillalsoidentifyspecificcharacteristicsthatcouldbestudiedfurthertodeveloppotentialwaysofimprovingmotorcyclesafety.AWSDOTemployeeisontheprojectpanelforthisresearch.


Chapter 2: CablebarrierpolicyandupdateofWSDOTactions

Washington’spolicyforcablemedianbarrierusagehasbeenevolvingsince1995whenWSDOT’sDesignManualfirstpresentedguidanceonuseofcablebarrierinhighwaymedians.Ourguidanceisexpectedtocontinuethisevolutionascablebarriersystemsevolveandmoreislearnedaboutcablebarrierplacementandperformance.In2007,WSDOThiredDr.MalcolmRay,PE,Ph.D.,toconductanindependentevaluationofourcablemedianbarrierpolicyandprogram.Dr.Raypresentedhisfindingsinthe2007“CableMedianBarrierReassessmentandRecommendations”reporttoGovernorChristineGregoire.Inthatreport,Dr.RaysubmittedseveralrecommendationsregardingWSDOT’spolicyoncrossmedianprotection.Intheupdated2008report,Dr.RayreviewedandcommentedonWSDOT’sprogresstowardimplementinghisrecommendationsandofferedupdatedrecommendationsforthefuture.AlthoughDr.Raywasnotconsultedinthisreport,thischapterpresentsanupdatetohispolicyandresearchrecommendationspublishedinthe2008report.

Policy RecommendationsPolicy Recommendation No. 1 - Installation of cable barrier

I recommend that WSDOT continue its use of cable median barrier. The cable median barrier program has been very effective statewide in reducing the number and severity of median cross-over crashes and has doubtless saved many lives.

2008 recommendations/conclusion - WSDOT has adopted my recommendation that the cable median barrier continue to be used in Washington State.

Progresssince2008report-WSDOTcontinuestoinstallcablebarrierinthemedians.

Policy Recommendation No. 2 - Placement of barrier on slopes

When cable barriers must be placed near the breakpoint between a nominal 10:1 and nominal 6:1 slope in the median, the following options should be considered:

a. For single-runs of cable median barrier, if there is at least 13 feet from edge of the nearest traveled lane to the slope breakpoint, the cable median barrier should be placed at least one foot in front of (i.e., between the breakpoint and the traveled lane) the slope breakpoint. Any crash tested cable median barrier can be used in this situation (i.e., low-tension or high-tension). This arrangement will allow 12 feet of dynamic deflection distance for back-side hits, provide an adequate emergency lane, minimize the chance of bumper height problems associated with SUV’s and pickup trucks traversing slopes prior to contacting the barrier and provide some recovery space for vehicles leaving the near lanes of travel.

b. For double-runs of cable median barrier, if there is at least 11 feet from edge of the nearest traveled lane to the slope breakpoint, the cable median barrier should be placed at least one foot in front of the slope breakpoint. Any crash tested cable median barrier can be used in this situation (i.e., low-tension or high-tension). This arrangement will provide an adequate emergency lane, minimize the chance of bumper height problems associated with SUV’s and pickup trucks traversing slopes prior to contacting the barrier and provide some recovery room for vehicles leaving the near lanes of travel. Deflection distance for back-side hits are not as much of a concern in this situation since the back of one barrier is shielded by the barrier on the other side of the median.


c. When there is not sufficient space to position the barrier in front of the slope breakpoint, a cable median barrier with a wider window of protection should be used to minimize the chance of newer SUV and pickup trucks from over-riding the barrier. Other types of cable median barriers that can be used behind the slope break point are:

i. Any test level four-cable median barrier or

ii. A cable median barrier that is designed and crash tested such that its successful performance with newer SUVs and pickup trucks on terrains with typical slope breakpoints has been established.

While I do not believe that test level four barriers are appropriate for general highway conditions, the higher rail height of typical test level four barriers should provide additional protection for SUV’s in the interim period between the new full-scale crash testing guidelines being adopted and the development of new test level three hardware. I also encourage WSDOT to perform full-scale crash testing of cable median barriers on typical median cross-sections to develop barrier options with established performance on typical median cross-sections.

2008 recommendations/conclusion - Implementation of this recommendation is still in progress. There are several development efforts aimed at developing four-cable median barriers for use on 4:1 slopes and test level four barrier may also help address this need. If these new barriers are successfully tested on 4:1 slopes the placement on the slope should be less critical. WSDOT is in the process of revising its cable median barrier policy as reflected in Chapter 700 (Traffic Barriers) of the WSDOT Design Manual. The revision is expected to (1) removed the low-tension cable median barrier as an option for new installations, (2) add the slope placement details described in parts a and b of my recommendations and (3) recommend the use of test level four cable median barriers or four-cable median barriers. The revisions to the Design Manual should address this recommendation.

Progresssince2008report-WSDOThaspursuedDr.Ray’srecommendations.WehavemodifiedtheDesignManualto:precludelow-tensioncablebarrierasanoptionfornewinstallations,addedslopeplacementguidance,andrecommendfourcablebarrierssystems.Wehavecontractsinprogressthatwillinstallsomeofthefourcablesystemsapprovedforuseon4H:1Vslopes.Wewillcontinuetomonitortheevolutionofcablebarriersystemstoidentifysystemsthatofferenhancedperformance.

Policy Recommendation No. 3 - Field inspection of connections

WSDOT should develop a field inspection procedure to ensure that all wedge-and-socket connections are sound and the wedges are firmly seated into the sockets. All such connections on the low-tension cable median barriers should be field checked in a reasonable period of time to ensure that the cable forces are correctly transmitted to the foundation.

2008 recommendations/conclusions - WSDOT has adopted my recommendation and quickly performed the field inspections to ensure the socket-and-wedge connection in the low-tension cable median barrier were properly seated.

Progresssince2008report-WSDOTchecksthewedge-and-socketconnectionsoflow-tensioncablebarrierduringmaintenanceandrepairsofthelow-tensioncablebarriersystems.Projectsadvertisedandawardedinthesummerof2009willreplacenearlyalloftheexistinglow-tensioncablebarriersinstallationswithfourcablehigh-tensionsystems.Withhigh-tensioncablebarriersystems,theconstantcabletensionkeepsanywedgesseatedfirmlyinthesockets.


Policy Recommendation No. 4 - Crash history as a basis for installing barrier

WSDOT should develop install recommendations based on a periodic review of crash history for installing both cable median barrier and concrete median barrier. Currently, installation recommendations are based primarily on the median characteristics such as median width and traffic volume. Engineering judgment and installation recommendations based on highway geometry should be the first criteria in deciding on locations for median barrier but crash history should also play a role for locations like Marysville where the site geometry are simply not accurate predictors of the magnitude of the cross-median problem.

2008 recommendations/conclusion - In reviewing the screening criteria I would like to make one small suggestion for a change. Currently, the note on Table 6 reads “ crash rates should be calculated on sections that are at least two miles long and, where data are available, the section has experienced at least 100 MVMT.” ……… I believe it would be more accurate and realistic to not calculate the rate until the vehicle miles travelled exceed 200 MVMT. I also believe the section length criterion can be dropped since a short section will simply take longer to meet the vehicle miles travelled criteria. I suggest that the note be changed to “crash rates should be calculated only on sections where the section has experienced at least 200 MVMT.

The quick comparison of the “old” WSDOT cable median barrier policy versus the “new” cable median barrier policy discussed earlier in this report raises very interesting questions about the evolution of median barrier policy. I recommend that WSDOT use the data assembled for this review and perform a more comprehensive review of the pre-2004 and post-2004 policies to see if it is possible to determine the effectiveness of low-tension versus high-tension cable median barrier and the effectiveness of the different versions of the placement policy. It may not be possible to separate these two effects but it should be possible to demonstrate that the post-2004 policy is an incremental improvement over the earlier policy.

Progresssince2008report-Inadditiontoexistingstateandfederalguidance,WSDOTdidconductaperformanceanalysisofexistingcablebarrierinstallations,incorporatingthemodificationstothescreeningcriteriarecommendbyDr.Rayinthe2008report.Thatanalysisrevealedthattherewere12locationswheretherateofcross-mediancollisionsexceededthe0.75collisionsper200millionvehiclemilesthresholdsuggestedbyDr.Ray.Eightofthesesectionsdidnotmeettheminimumexposure(200millionvehiclemilestraveled)forthebarrier.OneofthesesectionsdidnotmeettheminimumaveragedailytrafficvolumesuggestedbyDr.Ray.Oneoftheremainingsegments(PuyallupRivertoFifeonI-5)ismostlywithinthelimitsofaprogrammedprojectthatwillreplacethecablewithconcretebarrieraspartofalargerHOVlaneproject.Becauseofpermittingissues,theremainingportion(0.99mile)ofthisinstallationcouldnotbeincludedintherecentfederalstimulus-fundsprojects.TheremainingsegmentnearthePuyallupRiverwillbeslatedforretrofitorreplacementwhenprojectfundingisidentified.Theremainingtwosectionsareasfollows:

I-5, Nisqually: Thissectionhasacross-mediancollisionrateof1.19.Thisinstallationcurrentlyhasalow-tensioncablebarriersystemandisincludedinthefederalstimulusfundedcontractsthatwillplaceafour-cablehightensionsysteminthemedian.

SR-512, Puyallup: Thissectionhasacross-mediancollisionrateof0.95.Thisinstallationcurrentlyhasahigh-tensioncablebarriersysteminplace.WSDOTisevaluatingthislocationforanappropriatebarriersystemtoimprovetheperformance.

14H:1Vreferstoasloperatiooffourfeethorizontaldistanceforeachonefootofelevationchange.


Inthe2008cablebarrierreportDr.RayrecommendedthatWSDOTperformamorecomprehensivereviewoftheirpre-2004andpost-2004placementguidance-ifthatanalysiscouldbeseparatedfromthelow-tensionandhigh-tensionbarriercomparison.WerevisedourplacementpolicyinMay2004,identifyinglocationswithinthemediancross-sectionwherecablebarrierplacementshouldbeavoided.PriortoMay2004allofourinstallationswerelow-tensioncablebarrier.AfterMay2004,97.6percentofthemileageinstalledwashigh-tensioncablebarrier.Lookingmorecloselyatcollisionswiththelow-tensioncablebarrierinstallationswefindthat8.7percentofthosecollisionsoccurredinsegmentsthatwerecompletedaftertheplacementpolicychanged.Comparingthosecollisions,wefindinsignificantdifferences(fractionsofapercentage)inthepercentagesofvehiclescontainedinthemedian,crossmedian,orredirected.Thecrossmedianpercentagewas6.1percentofthetotalpriortothepolicychangeand5.3percentafterthepolicychange.ChangesininjuryseveritieswerealsoinsignificantwithfractionsofapercentagedifferenceininjuryseverityWeconcludedthattheshiftinpolicyissocloselylinkedtotheshiftinbarriertype,thatweareunabletoisolatetheimpactsofthepolicychange.

Research RecommendationsResearch Recommendation No. 1 - Placement in the median

Research on the proper placement of cable median barriers is desperately needed. The only guidance in this area is either outdated or never completed. Recently some crash tests of high-tension cable median barriers have been performed on 4:1 slopes but a comprehensive study of vehicle behavior when traversing typical depressed medians is needed to determine exactly where barriers should and should not be located. A new NCHRP project is programmed for this year that will look at the issue of guardrail and median barrier placement on slopes. NCHRP 22-22, Placement of Traffic Barriers on Roadside and Median Slopes,” will examine a variety of types of guardrails and median barriers placed on slopes so it should be possible for WSDOT personnel to encourage the project team to include the issues of cable median barrier placement in the project scope. NCHRP 17-22, “Identification of Vehicular Impact Conditions Associated with Serious Ran-Off-Road Crashes,” is examining real-world impact conditions to try and re-examine the most relevant crash test conditions. This project has been active since 2001 and has recently been expanded.

2008 recommendations/conclusion - WSDOT has implemented my recommendation and is both participating in and observing research efforts on cable median barrier taking place nationally.

Progresssince2008report-WSDOTisawaitingthecompletionofNCHRPProject17-22inlate2009.Project22-22hasnotmovedforwardoverthepastyear.NCHRPProject22-25“DevelopmentofGuidancefortheSelection,UseandMaintenanceofCableBarrierSystemswasproposedbyWSDOT,fundedbyNCHRP,andisinprogresswithaWSDOTemployeeonthepanel.ThisprojectisscheduledforcompletioninMarch2010.

Research Recommendation No. 2 - Higher bumper heights of pickups and SUVs

As discussed earlier, pickup trucks and SUVs have continued to become larger resulting in increasing bumper heights. Newer pickup trucks and SUVs may not perform well in impacts with some types of roadside hardware due to the miss-match between the barrier heights and bumpers. NCHRP 22-14(3), Evaluation of Existing Roadside Safety Hardware Using Updated Criteria, is a new project that will perform crash tests of existing hardware like cable median


barriers using the new proposed updated crash test procedures. Since the new crash test procedures recommend the use of newer pickup trucks with higher bumpers, some of the questions regarding bumper and barrier compatibility should be resolved. The Midwest Roadside Safety Facility at the University of Nebraska is also developing a new four-cable median barrier system that may provide some insight into the interaction of newer pickups and SUVs and cable median barriers.

2008 recommendations/conclusion - There are many activities going on nationally in this regard but some that particularly impact cable median barriers are Midwest Roadside Safety Facilities on-going efforts to design and crash test a four-cable median barrier, testing by several of the proprietary cable median barrier manufacturers to develop test level four cable median barriers and efforts to perform crash tests of several types of common roadside hardware with the new MASH 2008 pickup truck test vehicle. All these efforts are continuing and WSDOT personnel are monitoring these efforts.

Progresssince2008report-TheManualonAssessingSafetyHardware(MASH)wasadoptedbyAASHTOinmid-2009throughareviewandcommentprocess.AnFHWAimplementationplanisincludedinthismanual.Thefinalguidancewillbepublishedinlate2009.Thisdocumentprovidesrevisedguidanceonstandardizedcrashtestcriteriaincludingupdatedinformationontestvehicles.Thelargepickupselectedasthestandardtestvehiclehasabumperheightthatisapproximatelyfourincheshigherthanthepreviousguidance.ThecriteriaalsoprovidemoreguidanceonthetestingofcablebarriersystemsthanthepreviousguidanceunderNCHRPReport350.

MidwestRoadsideSafetyFacilitycontinuesworkontheirfour-cable-hightensiondesign,sponsoredbyseveralstatesinapooledfundresearchproject.Therewasasetbackinthecrashtestingduring2008,whichrequiredaredesignofthecabletopostattachmentbracket.Thestatesinvolvedinthepooledfundeffortcontinuetosupportthisprojectwithfundingcontributions,anddesignguidance.Thebracketredesigniswellunderwayandifallgoeswell,thesystemwillbecrashtestedinfall2009.

Research Recommendation No. 3 - Traffic conditions that promote median crossovers

The conditions that promote cross-median crashes are not well understood. Traffic conflicts and impaired drivers seem to initiate most cross-median crashes but it has been difficult to predict which sites will respond well to treatment with cable median barriers and which should use concrete median barriers. Traffic conditions like volume, mixing, interchange spacing, land use and speed limits appear to be related to the likelihood of cross-median crashes. Research should be performed to find good ways of predicting locations where cross-median crashes will be a problem. Such research would enable engineers to be pro-active and create designs that address a problem before fatal and disabling crashes occur.

2008 recommendations/conclusion - WSDOT acted on my recommendation and was able to get a new NCHRP project funded to investigate this issue.

Progresssince2008report-ThisprojectresultedinaresearchcontractawardedtoMidwestResearchInstituteinKansasCity,MO.ThecontractwasawardedinMarch2009withascheduledcompletioninmid-2011.AWSDOTemployeeservesontheprojectpaneltohelpguidethedirectionofthisresearch.


Chapter 3: UpdatestomedianbarrieronI-5inMarysville

Implementing recommendations to modify the I-5 median barrier system in MarysvilleTheJune2007CableMedianBarrierreportnotedahigher-than-averagenumberofcrossovercollisionsonI-5inMarysville.Asaresult,independentexpertDr.MalcolmRayrecommendedinstallingconcretemedianbarrierandwideningtheshoulderalongnorth-boundI-5inMarysvilletoprovidethehighestlevelofprotectionagainstcrossovercollisions.Therehaven’tbeenanycross-mediancollisionsinthesegmentsinceFebruary2007.

Followingtheserecommendations,inDecember2007Gov.Gregoireallocated$26.9milliontoreplacetheexistinglow-tensioncablemedianbarrierwithconcretebarrieralong10milesofnorthboundI-5inMarysville.ThefundingwasapprovedbytheLegislatureinMarch2008,allowingWSDOTengineerstobegindesigningtheproject.

Followingenvironmentalprocesses,permitacquisition,andprojectdesign,weadvertisedtheMarysvillemedianbarrierprojectforcompetitivebidsinApril2009,andinJuneawardedthecontracttoTri-StateConstruction,Inc.,whosubmittedthemostcompetitivebidat$18.9million.ConstructionbeganinlateJulyandisexpectedtobecompletebylate2010.Barrierinstallationisexpectedtobecompletebyspring2010.Totalprojectcompletionisexpectedinlate2010.Moreinformationisavailableat:www.wsdot.wa.gov/Projects/I5/MarysvilleMedianBarrier

How will the new median barrier system help to reduce crossover collisions?ThenewMarysvillemedianbarriersystemwillinclude10milesofconcretemedianbarrierandawidened10-footshoulderalongthenorthboundlanesofI-5fromStateRoute528toStateRoute530.Widershoulderswillgivenorthbounddriverswholosecontroloftheirvehicleadditionalroomtoslowdown,regaincontrol,andre-entertraffic,whileincreasingtheirchancesofavoidingacollisionwiththemedianbarrier.Ifanorthboundvehicleleavestheroadwayandcollideswiththeconcretemedianbarrier,thebarriershouldreducethefrequencyofvehiclescrossingthefreewaymedian.

Theexistinghigh-tensioncablebarriersystemalongthesouthboundlaneswillremaininplacetoprovideredundantprotectionagainstsouthbounddriverscrossingintonorthboundlanes.SouthbounddriverswhorunoffthefreewaywillhitcablemedianbarrieronthatsideofI-5,whichwillabsorbmuchoftheforceofimpact,reducetheriskofarollover,andreducetheriskofreboundcollisionsthatinvolveothervehicles.Ifthecablemedianbarrierdoesnotrestrainthevehiclewithinthemedian,itwilllikelydecelerateandredirectuponimpactwiththeconcretemedianbarrieralongthenorthboundlanes.

Federal stimulus funding broadened the scope of the Marysville barrier project InFebruary2009WSDOTreceivedanadditional$2.5millionfromtheAmericanRecoveryandReinvestmentAct(ARRA)toinstallIntelligentTransportationSystems(ITS)alongI-5inMarysville.Thisfundingwillbeusedtoinstall11trafficcameras,anoverheadmessagesign,10milesoffibercommunicationsconduit,andtrafficdatadetectorsalongI-5inMarysville.TheseITS


componentswillimprovefreewayoperationsandprovidereal-timetrafficinformationformotorists.

What has happened on I-5 in Marysville since the last report?In2008,atotalof46collisionsinvolvingcablemedianbarrieroccurredinMarysville.Noneofthesecollisionsresultedinfatalities,andonlysixresultedinaninjury.


Chapter 4: Nextsteps

ThemedianlocationsidentifiedbyWSDOTin2002forbarriertreatmentareeithercompleteorundercontract.Theselocationstargetedfullaccess-controlledhighwayswithmediansupto50feetinwidth.Inadditiontotheselocations,wehaveidentifiedpartialaccess-controlledhighwaysthatwepredictwillbenefitfromsimilarinstallations.

Future planned installations ThereareprojectsplannedtoinstallcablebarrieronsegmentsofUS195,US395,andSR8.Theseinstallationsareplannedwithinthenexttwoyears.Whenalloftheplannedinstallationsarecomplete,weexpecttohave219milesofourhighwaymedianstreatedwithcablebarrier.

Inadditiontotreatingmedianswherenobarrierexists,weareaddressingcablebarriersystemsinmostofthelocationswherewefirstinstalledcablebarriersystems.TheAmericanRecovery&ReinvestmentActof2009(ARRA)offeredfundingopportunitiesforWSDOTprojectsthatwillplacefour-cablehigh-tensionbarriersysteminlocationswherethree-cablelow-tensionbarriercurrentlyexist.Thefour-cablesystemsplannedfortheselocationswillprovideahighertopcableandlowerbottomcablethanthesystemcurrentlyinplace.Theexpandedrangeofcableheightsreducetheprobabilityofvehiclesgettingunderoroverthebarrier.TheARRAprojectsareexpectedtobeundercontractin2009.

We will consider new developments in cable barrier technology for future designs and installationsOngoingresearchanddevelopmentofcablebarriersystemshavebeendirectedtowardshigh-tensioncablebarriers,systemswithabroaderrangeofcableheights,andsystemstestedonsteeperslopes.Weanticipatethattheseeffortswillcontinue,andwewillmonitorfuturedevelopmentsandadoptasappropriatedesignguidancethatreflectsthosedevelopments.

Onesucheffortthatweareawareofisevaluatingaretrofitofthethree-cablehigh-tensioncablesystemcurrentlyinplaceinmanyofourmedians.Thefocusoftheretrofiteffortisconversionofthoseinstallationstoafour-cablesystemwithahighertopcableandlowerbottomcable.WSDOTisengagedinthedevelopmentofthisretrofitandanticipatesasystemthatcomplieswithcrashtestguidanceandisdeemedacceptabletoFHWA.Tohelpoffsetthecostofsucharetrofit,ourARRAfundedcontractsremovingthelowtensioncablesystemsaresalvagingthecablesforuseasthefourthcableinthehightensionretrofits.

Cable barrier is being tested in narrow medians and in other applicationsInthe2008report,wenotedthattheOregonDepartmentofTransportation(ODOT)installedcablebarrierinapavedmedianthatisonlyeight-feetwideasanexperimentalinstallationonUS26(Mt.Hoodhighway).Thislocationhadexperiencedseveralcenterlinecrossovercollisions.ODOTplanstomonitorthisinstallationforafive-yearperiodtodeterminetheeffectivenessofthebarrierandpotentialforuseinsimilarconditions.Afterapproximatelytwoyearsinservice,ODOTreports,thattherehaven’tbeenanyinjuryaccidentsassociatedwithcollisionstothisbarrier(asofJune2008).It’sestimatedthat30to40percentofhitstothisinstallationsareinstanceswheretheimpactingvehiclessimplydriveoff.


More states are using cable barrier systemsInpreparingtheJune2007cablebarrierreport,wehadconsultedotherstatesregardingtheiruseofcablemedianbarriersystems.Attheendof2006therewere14statesthathadnotinstalledanycablebarrier.Thatequatesto72percentofstates.Nowtwoyearslater,thereareonlyfourstatesthathavenocablebarrierthemedians.92percentofthecountryhasadoptedcablebarrierforuseasamedianbarrier.Figure(s)4-1&4-2provideacomparisonofstatesusingcablebarrierasof2006versus2008.

Figure 4-1

Washington

Nevada

California

Arizona

Alaska

Oregon

Idaho

Utah

Montana North Dakota

Minnesota

Wisconsin

Michigan

IndianaOhio

Pennsylvania

WestVirginia

SouthCarolina

Massachusetts

Rhode IslandConnecticut

New Jersey

Delaware

Maryland

Vermont

New York

New Hampshire

Maine

Illinois

South Dakota

Nebraska

Iowa

Kansas Missouri

Arkansas

Mississippi

Louisiana

AlabamaGeorgia

Florida

Tennessee

North Carolina

Kentucky

Virginia

Oklahoma

Texas

Wyoming

Colorado

New Mexico

Hawaii

States that did have cable median barriers in 2006

States that did not have cable median barriers in 2006

Figure 4-2 Cable Median Barrier Usage in 2008

Cable Median Barrier Usage in 2006


Appendix A: Cable Median Barrier Trends and Performance

193

Appendix A: Statewide Cable Median Barrier Installations

Design, Standards, & Research

I-5 Vancouver

I-5 Longview

US 12 Montesano

I-82 Yakima

I-5 Lewis Co.

US 101 Olympia

I-5 Nisqually

SR 3 Silverdale

SR 16 Olympic Dr./Purdy

SR 16 Burley-Olalla

I-90 E. of Spokane

I-90 East Moses Lake

I-90 Moses LakeI-90 George to Moses Lake

I-90 George

I-90 Vantage

I-90 Cle Elum

I-82 ProsserI-182 Pasco

SR 240 Richland

SR 539 Ten Mile Rd.I-5 Blaine

I-5 Ferndale

I-5 Bellingham

I-5 N. of Burlington

SR 20 Fredonia

I-5 Mount Vernon

I-5 Marysville

SR 512 Puyallup

SR 410 Sumner

I-5 FifeSR 167 Sumner

SR 18 CovingtonSR 18 SE 312th

SR 99 Tukwila

I-90 Issaquah

I-90 Bellevue

SR 522 Bothell

US 12 Yakima

Cable Barrier Construction Status

CompleteUnder Construction

Cable Median Barrier Status as of 12/31/08


Appendix B: Location, installation and performance data from review of cable median barrier installations in Washington state

The data sheets that follow contain information about each location where cable median barrier was installed or under construction along Washington state highways at the end of 2008. The before-and-after collision data shows the number of crashes, by severity, that occurred in the median and crossed the median in each location before and after cable median barriers were installed.

WSDOT reviewed five years of data from crashes that occurred before cable median barrier was installed in each location, with the exception of I-5 in Marysville. Only 2 ½ years of before cable data is available for this location, because it was the first location where cable median barrier was installed in Washington state. Data ranges from crashes after cable median barrier was installed from a few months to a few years because all available data was included in the analysis. The barrier was installed at different times in each location.

Data also is presented for four representative highway sections where concrete barrier is in place. For these sections, data is presented only for crashes that occurred after concrete median barrier was installed because some of the concrete barriers have been in place for over 20 years.

All collision data was obtained by reviewing the collision history provided by the WSDOT Transportation Data Office and by reviewing WSP collision reports for all collisions that occurred after barrier was installed. Overall, WSDOT staff reviewed data from more that 11,700 collisions and examined more than 3,900 individual collision reports.


SR 3 SilverdaleMilepost 38.53 to 53.18

Bremerton

Silverdale

Poulsbo

3

3

305308

303

K I T S A PC O U N T Y

Puget Sound

BainbridgeIsland

N

Milepost 38.53 - 45.23Length: 6.70 milesMedian width: 38-68 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2007

SR 3 Silverdale (38.53 - 45.23) No injury

Possible injury

Evidentinjury

Serious injury Fatality

All median collisions before (60 months) 12 10 1 8 0

All median collisions after (19 months) 24 5 1 0 0

Cross median collisions before (60 months) 2 1 0 4 0

Cross median collisions after (19 months) 0 0 0 0 0

No cross-median incidents have occurred since we installed this cable median barrier.

The cable median barrier through this area is generally located 10 feet from the edge of the eastbound lanes.

South of Silverdale

North of Silverdale

Source: WSDOT Traf�c Data Of�ce

95 97 99 01 03 05 070

50,000

100,000

150,000

200,000

Average annual daily traffic volumeVehicles per day by year

Cable barrierinstalled

ADT average growth rate on segment north of Silverdale is 4 percent per year.

ADT average growth rate on segment south of Silverdale is 2 percent per year.

Milepost: 45.51 - 45.98Length: .47 milesMedian width: 24-36 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2008


Possible injury

Evidentinjury



All median collisions after (less than one month) 0 0 0 0 0


Cross median collisions after (less than one month) 0 0 0 0 0

Milepost: 46.38 - 53.18Length: 6.8 milesMedian width: 38-48 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2008


Possible injury

Evidentinjury






© 2005 Tele Atlas


I-5 VancouverLength: 13.58 milesMedian width: 48-374 feet Speed limit: 60-70 mph Barrier type: Low-tensionYear installed: 2001

5

205

502

501

503

N

Vancouver

Colum

bia River

E. Fork Lewis River

C L A R KC O U N T Y

60 mph70 mph

I-5 Vancouver Milepost 7.8 to 11.10 and 12.28 to 22.56

I-5 Vancouver No injury

Possible injury

Evidentinjury






The cable median barrier through this area generally is located 14 to 34 feet from the edge of the northbound lanes.

Six cross-median incidents have occurred since we installed this cable median barrier:

• Two collisions involved vehicles that crossed the median and hit other vehicles traveling in the opposite direction.

• Three collisions occurred between mileposts 8.17 and 9.36.

• Five collisions involved southbound vehicles traveling across the median.


95 97 99 01 03 05 070

50,000

100,000

150,000

200,000



ADT average growth rate on segment is 4 percent per year.

© 2005 Tele Atlas


I-5 LongviewMilepost 37.42 to 40.45

I-5 LongviewLength: 3.03 milesMedian width: 48 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2010


95 97 99 01 03 05 070

50,000

100,000

150,000

200,000


I-5 Longview No injury

Possible injury

Evidentinjury



All median collisions after (0 months) No Data


Cross median collisions after (0 months) No Data

UV4 UV411

N

Cowlitz

© 2005 Tele Atlas 432

55

This cable barrier project is scheduled to be installed prior to Fall 2010.

Cable barrier is being removed from the Grand Mound to Maytown area of I-5 due to widening of the roadway. This removed hardware will be installed in this area of the interstate under the same contract.

© 2005 Tele Atlas


I-5 Lewis County line to MaytownMilepost 85.28 to 95.7

5

507

121

Maytown

T H U R S T O NC O U N T YL E W I S C O U N T Y

N

12HighTensionLowTension

Lewis County line to US 12Length: 3.05 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: Low-tensionYear installed: 2004US 12 to MaytownLength: 7.37 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2006

Lewis County line to US 12 No injury

Possible injury

Evidentinjury






US 12 to Maytown No injury

Possible injury

Evidentinjury






The cable median barrier in the southern three miles generally is located in the center of the median, 20 feet from the edge of each roadway. The cable median barrier in the northern 7.3 miles generally is located 12 feet from the edge of the northbound lanes. We installed the barrier in two separate construction projects.

Four cross-median incidents have occurred since we installed these cable median barriers.

• A northbound vehicle crossed through the median and struck a vehicle traveling in the opposite direction.

• A southbound vehicle crossed through the median and came to rest in the northbound lanes without striking another vehicle.

• A southbound vehicle crossed through the median and struck a northbound vehicle, resulting in a fatality collision.

• A southbound vehicle crossed through the median and came to rest in the northbound lanes without striking another vehicle.

The cable barrier throughout the above segments is being removed as part of an ongoing contract to widen the interstate to three lanes each direction.

This cable barrier will be re-used in a Longview segment that will be installed as part of the same contract.


Maytown

Lewis County


95 97 99 01 03 05 070

50,000

100,000

150,000

200,000



© 2005 Tele Atlas


I-5 NisquallyLength: 1.55 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2004*

I-5 NisquallyMilepost 112.66 to 114.28

510

Puget Sound

Nisqually River

Nisqually NationalWildlife Refuge

N

T H U R S T O N C O U N T Y

P I E R C E C O U N T Y

5

I-5 Nisqually No injury

Possible injury

Evidentinjury


All median collisions before (60 months) 6 1** 1 2 1




* A short section (.14 miles) was installed in 2005.**A possible injury collision has been removed from the before period dataset. It was found to have been a w-beam guard rail collision and no cable barrier involvement.

The cable median barrier generally is located 12 feet from the edge of the northbound lanes.

Three cross-median incidents have occurred since we installed this cable median barrier.

• A southbound vehicle traveled across the median, overturned and came to rest in the northbound lanes without striking another vehicle.

• A southbound semi truck and trailer traveled across the median and came to rest in the northbound lanes without striking another vehicle.

• A southbound vehicle lost control, spinning into the median where it traveled over the cable barrier, it entered the northbound lanes colliding with a vehicle.



95 97 99 01 03 05 070

50,000

100,000

150,000

200,000



© 2005 Tele Atlas


I-5 Puyallup River and Fife Milepost 135.62 to 137.41 and 137.49 to 139.02

!(

!(

Milton

Fife

Tacoma

5

5

508

99

161

CommencementBay

Puyallup River

N

P I E R C E C OU N T Y

K I N G C O

U N T Y

I-5 Puyallup RiverSegment Length: 1.79 milesMedian width: 48 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2004

I-5 FifeSegment Length: 1.53 milesMedian width: 48 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2001

I-5 Puyallup River No injury

Possible injury

Evidentinjury


All median collisions before (60 months) 9 5 3 1 2*




I-5 Fife No injury

Possible injury

Evidentinjury








95 97 99 01 03 05 070

50,000

100,000

150,000

200,000


*Includes one fatality which occurred during the early construction period. A southbound vehicle left the roadway, struck an embankment and crossed into northbound lanes. The driver was ejected into the northbound lanes.

One fatal cross-median crash occurred in 2007 when a southbound vehicle traveling at high speed failed to negotiate the curve. The vehicle traveled under the cable barrier, through the median and engaged three northbound vehicles.

The cable median barrier through this area generally is located 14 feet from the edge of the southbound I-5 lanes.

Twelve cross-median incidents have occurred since we installed cable median barrier

• Five involved vehicles that hit other vehicles traveling in the opposite direction.

• Eight occurred between milepost 138.17 and 138.71, in the vicinity of a significant curve.

• Eight involved southbound vehicles traveling across the median.

• I-5 Fife segment length was shortened from 2.0 miles to current length due to HOV project in the area.


© 2005 Tele Atlas


I-5 MarysvilleFirst installation, Milepost 201.58 to 203.69 Second installation, Milepost 199.34 to 209.28Third installation, Milepost 199.34 to 209.31 (double run)

I-5 Marysville first installation (dashed line)Segment Length: 2.11 milesMedian width: 40 feet Speed limit: 60 mph* Barrier type: Low-tensionYear installed: 1995

I-5 Marysville second installationSegment Length: 7.74 milesMedian width: 40 feet Speed limit: 60-70 mph*Barrier type: Low-tensionYear installed: 2000

I-5 Marysville third installationSegment Length: 9.80 milesMedian width: 40 feet Speed limit: 60-70 mph*Barrier type: High-tensionYear installed: 2007

N5

9

528

531

530

Marysville

SmokeyPoint

Arlington

92

PugetSound

S N O H O M I S HC O U N T Y

I-5 Marysville, first installation No injury

Possible injury

Evidentinjury



All median collisions after (135 months) 70*** 14*** 8 2 3



I-5 Marysville, second installation No injury

Possible injury

Evidentinjury



All median collisions after (84 months) 157 30 24 3 5**


Cross median collisions after (84 months) 3 6 3 2 4**

The cable median barrier through this area generally is located 16 feet from the edge of the northbound I-5 lanes. In early 2007 we installed a second run of cable median barrier along the southbound lanes, generally 12 feet from the edge of the lanes.

We changed the posted speed limit from 70 mph to 60 mph on July 1, 2005.

Twenty-three cross-median incidents have occurred since we installed cable median barrier, through 2007:

• Fourteen collisions involved vehicles that crossed over the median and hit other vehicles traveling in the opposite direction.


0

50,000

100,000

150,000

200,000


South of SR 531

North of SR 531

95 97 99 01 03 05 07



I-5 Marysville, third installation No injury

Possible injury

Evidentinjury




* Posted speed changed from 70 mph to 60 mph on July 1, 2005** Cross median fatality collision occurred during construction phase of third installation (was previously reported in the third installation segment).***Six collisions previously reported in first installation are now shown in third install.

© 2005 Tele Atlas


• Thirteen incidents, including three fatal crashes, occurred between milepost 204.29 and 207.5, an area that includes the SR 531 interchange and the Smokey Point Rest Area entrances and exits to the north.

• Five, including one fatal crash, occurred between milepost 201.5 and 203.3 includes the 116th Street interchange.

• Nineteen of these collisions involved southbound vehicles traveling across the median

Eight fatal median-related crashes have occurred since we installed the cable barrier, through 2008:

• Five of these incidents involved vehicles that crossed over the median.

• Seven of these incidents involved the cable barrier: in two collisions, vehicles rolled over, and passengers were ejected; in one collision, a vehicle traveling in the wrong direction hit another vehicle, causing one of these vehicles to hit the cable median barrier.

• One fatal crash involved a vehicle that hit the median bridge column at 116th Street but did not hit the cable median barrier.


I-5 Mount VernonMilepost 215.12 to 225.48

!(

!(

!(

Mount Vernon

La Conner

Stanwood

S K A G I TC O U N T Y

S N O H O M I S HC O U N T Y

5

532

534

9

9

538536

20

I S L A N DC O U N T Y

N

PugetSound

70 mph60 mph

I-5 Mount VernonLength: 10.36 milesMedian width: 40-76 feet Speed limit: 60-70 mph Barrier type: High-tensionYear installed: 2006

I-5 Mount Vernon No injury

Possible injury

Evidentinjury







One cross-median incident has occurred since we installed this cable median barrier. In this instance a northbound tow truck struck the barrier and stretched the cables into the southbound roadway. No other vehicles were involved.


0

50,000

100,000

150,000

200,000


Cable barrierInstalled

95 97 99 01 03 05 07


© 2005 Tele Atlas


I-5 North of BurlingtonMilepost 230.9 to 234.61

!(

Burlington

5

20

20

11

Skagit River

N

S K A G I TC O U N T Y

5

I-5 North of BurlingtonLength: 3.71 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2006

I-5 north of Burlington No injury

Possible injury

Evidentinjury


All median collisions before (60 months) 18 9 5 4 2*




The cable median barrier generally is located 10 to 12 feet from the edge of the southbound lanes.

One cross-median incident has occurred since we installed this cable median barrier. However, this occurred at an official median crossing and no cable median barrier was involved. This was a single vehicle incident.


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07

ADT average growth rate on segment, 2 percent per year.

© 2005 Tele Atlas

* A fatal cross-median collision was removed from the before period as it was found to occur during the construction period of the cable barrier installation. Construction period collisions are not reported in this document.


5

5

539

542

BellinghamBellingham Bay

LakeWhatcom

11

N

W H AT C O M C O U N T Y

HighTensionLow Tension

Low Tension

Low Tension

HighTension

I-5 South Bellingham to Bakerview RoadMilepost 250.96 to 258.27

I-5 south Bellingham Length: 0.37 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 1999I-5 Bellingham Length: 0.82 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006 I-5 north Bellingham Length: 1.63 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2003Squalicum Creek to Bakerview RoadLength: 2.82 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

I-5 south Bellingham No injury

Possible injury

Evidentinjury






I-5 Bellingham No injury

Possible injury

Evidentinjury






I-5 north Bellingham No injury

Possible injury

Evidentinjury






I-5 Squalicum Creek to Bakerview Road

No injury

Possible injury

Evidentinjury






© 2005 Tele Atlas


The cable median barrier generally is located 10 to 12 feet from the edge of the northbound lanes.

There have been three cross median barrier incidents since this barrier was installed.

• A northbound vehicle lost control entering the median, engaged the cable barrier but slipped under and came to rest in the southbound lanes without striking another vehicle.

• A northbound vehicle enters the median and impacts the cable barrier, the vehicle and cable comes to rest in the southbound lanes. A southbound vehicle struck the stretched cable in its travel lane.

• A northbound vehicle enters the median and slips through the barrier striking a southbound vehicle.

ADT average growth rate on segment north of Bellingham is 4 percent per year.

ADT average growth rate on segment from Bellingham to Bakerview Road is 2 percent per year.


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07

North of SR 542

South of SR 542

NorthSouth


I-5 FerndaleMilepost 262.41 to 266.00

!(

5

5Ferndale

Lake Terrell

NooksackRiver

548

N

W H AT C O MC O U N T Y

I-5 FerndaleLength: 3.59 milesMedian width: 40-76 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2006

I-5 Ferndale No injury

Possible injury

Evidentinjury







Two cross-median incidents have occurred since we installed this cable median barrier.

• A southbound vehicle entered the median and passed through the cable barrier coming to rest in the northbound lanes without striking another vehicle.

• A northbound vehicle crossed through the median coming to rest off the right of the southbound lanes, no other vehicles were involved.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


I-5 BlaineMilepost 273.93 to 276.14

Blaine

Drayton Harbor

Semiahmoo Bay

C A N A D A

W H AT C O MC O U N T Y

NHighTension

LowTension5

543

548

I-5 BlaineLength: 2.21 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tension and low-tensionYear installed: 2006*

I-5 Blaine No injury

Possible injury

Evidentinjury






* A short section (0.27 miles) was installed in 2000 but is not broken out separately because of the short distance

The cable median barrier generally is located 10 feet from the edge of the southbound lanes.



0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


ADT average growth rate on segment is -2 percent per year.

© 2005 Tele Atlas


US 12 MontesanoMilepost 9.11 to 20.95

!(

!(

12

1212

8

107

MontesanoElma

Chehalis River

WynoocheeRiver

SatsopRiver

Satsop

G R AY S H A R B O RC O U N T YN

US 12 MontesanoLength: 11.84 milesMedian width: 38-40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

US 12 Montesano No injury

Possible injury

Evidentinjury


All median collisions before (60 months) 20 3 3 3 0 *

All median collisions after (27 months) 54 4 2 1 0 *

Cross median collisions before (60 months) 3 2 2 2 0 *


The cable median barrier generally is located 12 feet from the edge of the eastbound lanes.


*A correction to the installations work started date resulted in a slight shift of the injury data from the previous year’s report to this report.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


US 12 YakimaMilepost 201.9 to 202.5

US 12 YakimaLength: 0.60 milesMedian width: 40 feetSpeed limit: 60 mphBarrier type: High-tensionYear installed: 2007

§̈¦82

£¤12

UV823 N

Yakima

US 12 Yakima No injury

Possible injury

Evidentinjury







0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


The cable median barrier generally is located 10-12 feet from the edge of the eastbound lanes.

One cross-median incident has occurred since we installed this cable median barrier.

• An eastbound vehicle struck the end of the cable median barrier and spun around coming to rest in the westbound lanes, no other vehicles were involved.

© 2005 Tele Atlas


SR 16 Olympic Drive to Burnham Drive Milepost 10.83 to 15.12Purdy Milepost 16.03 to 19.00

16

16

302

GigHarbor

K I T S A PC O U N T Y

P I E R C EC O U N T Y

K I N GC O U N T Y

Vashon IslandColvos

Passage

DalcoPassage

HendersonBay

N

SR 16 Olympic Drive to Burnham DriveLength: 4.29 milesMedian width: 53 feet Speed limit: 55-60 mph Barrier type: High-tensionYear installed: 2007

SR 16 Purdy Length: 2.97 milesMedian width: 54 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

SR 16 Olympic Drive to Burnham Drive

No injury

Possible injury

Evidentinjury






SR 16 Purdy No injury

Possible injury

Evidentinjury






The cable median barrier generally is located 10 to 12 feet from the edge of the eastbound lanes.


• A westbound vehicle entered the median rolling over the cable median barrier coming to rest in the eastbound lanes, no other vehicles were involved.


0

50,000

100,000

150,000

200,000


SR 16 Olympic Drive to Burham Drive

95 97 99 01 03 05 07


SR 16 Purdy

ADT average growth rate on Olympic/Burnham segment is 1 percent per year.

ADT average growth rate on Purdy segment is 2 percent per year.

© 2005 Tele Atlas


SR 16 Burley-OlallaMilepost 19.70 to 20.52

SR 16 Burley-OlallaLength: 0.82 milesMedian width: 80 feet Speed limit: 50 mph Barrier type: High-tensionYear installed: Late 2009

SR 16 Burley-Olalla No injury

Possible injury

Evidentinjury



All median collisions after No Data


Cross median collisions after No Data


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

Kitsap

N

Pierce

302 16

This cable barrier project is expected to be completed late 2009, nearly one year early from original construction schedule.

© 2005 Tele Atlas


SR 18 CovingtonMilepost 7.8 to 11.38

!(

18

18

516 516

Covington

Lake Meridian

N

K I N GC O U N T Y

SR 18 CovingtonLength: 2.38 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

SR 18 Covington No injury

Possible injury

Evidentinjury







0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07


SR 18 SE 312th VicinityLength: 0.09 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2004

SR 18 SE 312th Vicinity No injury

Possible injury

Evidentinjury






The cable median barrier generally is located nine to 10 feet from the edge of the southbound lanes.

There has been a single cross-median incident since we installed this barrier.

• A westbound vehicle lost control and entered the median. It struck both cable median barrier and w-beam guard rail in the median, it continued across the eastbound lanes coming to rest off the roadway without striking any other vehicles.

© 2005 Tele Atlas


SR 18 Issaquah/HobartMilepost 19.65 to 20.22

SR 18 Issaquah/HobartLength: 0.57 milesMedian width: 48 feet Speed limit: 55 mph Barrier type: High-tensionYear installed: 2008

SR 18 Issaquah/Hobart No injury

Possible injury

Evidentinjury




Cross median collisions before (60) 0 0 0 0 0



0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07

The cable median barrier generally is located 12 to 18 feet from the edge of the westbound lanes.


© 2005 Tele Atlas

UV18

UV169

N

Lake Francis

Lower Peterson Creek Corridor Natural Area

King


SR 20 FredoniaMilepost 54.72 to 56.50

SR 20 FredoniaLength: 1.78 milesMedian width: 40 feet Speed limit: 55 mph Barrier type: High-tensionYear installed: Late 2009

!(

§̈¦5

UV20

UV536

UV11

UV538

N

Mount Vernon

SR 20 Fredonia No injury

Possible injury

Evidentinjury


All median collisions before (60 months) No data

All median collisions after No data

Cross median collisions before (60 months) No data

Cross median collisions after No data


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07


This installation is to be completed as part of a 2-stage construction contract.

This area continues to be an active construction/work zone as other safety projects are completed. Expected completion is Fall 2009.

© 2005 Tele Atlas


I-82 YakimaMilepost 29.38 to 39.14

I-82 YakimaLength: 7.75 milesMedian width: 50 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2007

N

Yakima

Union Gap

§̈¦82

£¤12

£¤97

UV24

UV823

I-82 Yakima No injury

Possible injury

Evidentinjury






I-82 Yakima - Selah CreekLength: .57 milesMedian width: 50 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2008

I-82 Yakima - Selah Creek No injury

Possible injury

Evidentinjury







0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07



© 2005 Tele Atlas


I-82 ProsserMilepost 88.51 to 92.14

I-82 ProsserLength: 3.63 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2008

I-82 Prosser No injury

Possible injury

Evidentinjury






The cable median barrier through this area is generally installed 4 to 30 feet from the edge of the eastbound lanes.


Benton

221

22

82N

Prosser


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

© 2005 Tele Atlas


I-90 BellevueMilepost 11.75 to 12.05

I-90 Bellevue Length: .30 milesMedian width: 75 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2006

I-90 Bellevue No injury

Possible injury

Evidentinjury







Lake Sammamish

KING

§̈¦90

UV900

N

Bellevue


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07



© 2005 Tele Atlas


I-90 IssaquahMilepost 15.99 to 17.12

90

90

Issaquah

K I N G C O U N T Y

N

I-90 Issaquah Length: 1.13 milesMedian width: 48 feet Speed limit: 60 mph Barrier type: Low-tensionYear installed: 2005

I-90 Issaquah No injury

Possible injury

Evidentinjury









0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


I-90 Cle ElumMilepost 83.60 to 84.28

I-90 Cle ElumLength: 0.68 milesMedian width: 40-78 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2008

I-90 Cle Elum No injury

Possible injury

Evidentinjury






The cable median barrier through this area is installed generally 15 feet from the edge of the westbound lanes.


N

Cle Elum

Kittitas

90

903


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

© 2005 Tele Atlas


I-90 VantageMilepost 136.61 to 136.71

I-90 VantageLength: 0.1 milesMedian width: 30-50 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2007

§̈¦90

UV26

UV243

N

I-90 Vantage No injury

Possible injury

Evidentinjury



All median collisions after (13 month) 0 0 0 0 0


Cross median collisions after (13 month) 0 0 0 0 0


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07



© 2005 Tele Atlas


I-90 GeorgeMilepost 144.3 to 156.32

!(

!(

!(

!(

!(

!(

!(

PotholesReservoir

Ephrata

Moses Lake

Warden

George

Othello

90

90

Royal City

17

171

17

170262

26

243

Quincy

282

283

281

28

MosesLake

Colum

bia R.

AD

AM

S C

OU

NTY

GR

AN

T CO

UN

TY

N N N283

HighTension

LowTension

90

LowTension

I-90 GeorgeLength: 12.02 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2005

I-90 George No injury

Possible injury

Evidentinjury









0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


I-90 east of George to Moses Lake Milepost 160.70 to 170.39 and 173.70 to 174.52

I-90 east of George to Moses LakeLength: 10.51 milesMedian width: 38-40 feet Speed limit: 70 mph Barrier type: Low-tension and High-tensionYear installed: 2004, 2005*

I-90 east of George to Moses Lake No injury

Possible injury

Evidentinjury






!(

!(

!(

!(

!(

!(

!(

PotholesReservoir

Ephrata

Moses Lake

Warden

George

Othello

90

90

Royal City

17

171

17

170262

26

243

Quincy

282

283

281

28

MosesLake

Colum

bia R.

AD

AM

S C

OU

NTY

GR

AN

T CO

UN

TY

N N N283

HighTension

LowTension

90

LowTension


Four cross-median incidents have occurred since we installed this cable median barrier:

• None involved vehicles that hit other vehicles traveling in the opposite direction.

• Three collisions involved eastbound vehicles traveling across the median.

• Three collisions involved vehicles that rolled over.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

High Tension Installed

Low Tension Installed 2004


© 2005 Tele Atlas

* 3.45 miles of high tension cable was installed in 2005


I-90 East Moses LakeMilepost 179.70 to 192.10

I-90 East Moses LakeLength: 12.40 milesMedian width: 40 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2005

I-90 East Moses Lake No injury

Possible injury

Evidentinjury






!(

!(

!(

!(

!(

!(

!(

PotholesReservoir

Ephrata

Moses Lake

Warden

George

Othello

90

90

Royal City

17

171

17

170262

26

243

Quincy

282

283

281

28

MosesLake

Colum

bia R.

AD

AM

S C

OU

NTY

GR

AN

T CO

UN

TY

N N N283

HighTension

LowTension

90

LowTension

The cable median barrier generally is located 13 feet from the edge of the westbound lanes.

Two cross-median incidents have occurred since we installed this cable median barrier.

• A semi-truck traveling westbound crossed the median and came to rest in the eastbound lanes without hitting another vehicle.

• An eastbound vehicle crossed the median and came to rest on the westbound shoulder, no other vehicles were involved.

• One fatality collision occurred during 2007, an eastbound vehicle lost control entering the median. The vehicle rolled over several times but did not contact the cable median barrier.

• A fatal motorcycle collision occurred during 2008, the vehicle impacted the median cable barrier ejecting the operator.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

High Tension Installed

Low Tension Installed 2004


© 2005 Tele Atlas


I-90 SpokaneMilepost 292.18 to 299.46

I-90 east of SpokaneLength: 3.73 milesMedian width: 40 feet Speed limit: 60-70 mph Barrier type: High-tensionYear installed: 2004

I-90 east of Spokane-IILength: 3.13 milesMedian width: 40-76 feet Speed limit: 70 mph Barrier type: High-tensionYear installed: 2005

90

90

290

291

27

290

2395

2395

Spokane River

Liberty Lake

195

Spokane

Millwood

Liberty Lake

N

I DA

HO

S P O K A N E C O U N T Y

60 mph 70 mph

I-90 east of Spokane No injury

Possible injury

Evidentinjury






I-90 east of Spokane-II No injury

Possible injury

Evidentinjury







Nine cross-median incidents have occurred since we installed this cable median barrier:

• Three involved vehicles that crossed the median and hit another vehicle traveling in the opposite direction.

• Three occurred between mileposts 295.01 and 295.51.

• Seven involved westbound vehicles crossing the median.

• Three involved vehicles that rolled over into opposing lanes.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


East

East#2East of Barker Road

West of Barker Road

ADT average growth rate on both segments is 3 percent per year.

© 2005 Tele Atlas


SR 99 TukwilaMilepost 23.24 to 25.92

SR 99 TukwilaLength: 2.68 milesMedian width: 44 feet Speed limit: 60 mph *Barrier type: High-tensionYear installed: 2006

SR 99 Tukwila No injury

Possible injury

Evidentinjury






509

99

99

5

900

Tukwila

BoulevardPark

Seattle

N

Duw

amish W

aterway

S. Holden St.

Inte

rnat

iona

l Blv

d.

K I N G C O U N T Y



• A fatal motorcycle collision occurred in 2008. A northbound motorcycle was witnessed traveling at a high speed and reported doing wheelies prior to losing control and overturning in the travel lane. Rider separated from vehicle entering median and impacted the cable median barrier.

*0.14 miles of this segment has a posted speed limit of 40 mph.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


US 101 OlympiaMilepost 363.93 to 366.76

US 101 OlympiaLength: 2.83 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2007

US 101 Olympia No injury

Possible injury

Evidentinjury






101

5

5

Olympia

CapitolLake

Tumwater

N

T H U R S T O N C O U N T Y

The cable median barrier through this area generally is located 12 feet from the edge of the westbound lanes.


• A southbound vehicle lost control entering median, going under cable barrier and crossed northbound lanes. No other vehicles were involved.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


© 2005 Tele Atlas


SR 167 SumnerMilepost 6.86 to 11.44

SR 167 SumnerLength: 4.58 milesMedian width: 84 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

SR 167 Sumner No injury

Possible injury

Evidentinjury






167161

167 512 410

410

Edgewood

Sumner

N


Puyallup River




0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


I-182 PascoMilepost 12.3 to 15.19

I-182 PascoLength: 2.89 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2007

N Pasco

§̈¦182£¤12

£¤395

I-182 Pasco No injury

Possible injury

Evidentinjury







0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07

The cable median barrier generally is located in the center of the median, 16 to 23 feet from the edge of the eastbound lanes.


• An eastbound vehicle sideswiped an eastbound semi-tractor trailer and crossed the median coming to rest on the westbound shoulder, no other vehicles were involved.

© 2005 Tele Atlas


SR 240 RichlandMilepost 37.92 to 38.31

SR 240 RichlandLength: .36 milesMedian width: 70 feet Speed limit: 55 mph Barrier type: High-tensionYear installed: 2007

SR 240 Richland No injury

Possible injury

Evidentinjury






N

Richland

BENTON

FRANKLIN

�

UV240


0

50,000

100,000

150,000

200,000



95 97 99 01 03 05 07

The cable median barrier through this area generally is located 12 feet from the edge of the eastbound lanes.


© 2005 Tele Atlas


SR 410 SumnerMilepost 9.51 to 11.42

SR 410 SumnerLength: 1.91 milesMedian width: 40 feet Speed limit: 55 mph Barrier type: High-tensionYear installed: 2006

SR 410 Sumner No injury

Possible injury

Evidentinjury






Sumner

Bonney Lake

South Prarie

Buckley

Lake Tapps167

162

410

410

165

162

164

N

P I E R C EC O U N T Y

K I N G C O U N T Y

The cable median barrier varies between the eastbound and westbound side of the median and is located seven to 10 feet from the edge of the lanes.



0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07



© 2005 Tele Atlas


SR 512 PuyallupMilepost 2.48 to 11.99

SR 512 PuyallupLength: 9.51 milesMedian width: 40-65 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2007

SR 512 Puyallup No injury

Possible injury

Evidentinjury






512

512

512

7

7

167161

167

Puyallup River

Puyallup

161


N

The cable median barrier varies between the eastbound and westbound side of the median and generally is located 12 feet from the edge of the lanes.

This cable median barrier has contained two semi-trucks since early 2007, when it was installed.

Six cross median incidents have occurred since we installed this cable median barrier. Five fatality collisions have occurred in this section since its installation.

• A westbound vehicle lost control entering the median going under the cable barrier, colliding with an eastbound semi truck.

• An eastbound vehicle made a sudden lane change from the outside lane colliding with a semi truck. The vehicle entered the median colliding with the cable median barrier. The vehicle driver and a passenger died as the result of the collision.

• A westbound motorcycle operating at a high rate of speed lost control entering the median and struck the cable barrier.

• An eastbound vehicle entered the median and crossed through the cable barrier colliding with a westbound pickup truck and a semi-tractor trailer combination.

• A westbound semi-tractor trailer entered the median and drove over the cable barrier entering the eastbound travel lanes. An eastbound vehicle unable to avoid the trailer drove under the trailer shearing the vehicles roof off. An additional vehicle struck the semi-trailer.

95 97 99 01 03 05 07



0

50,000

100,000

150,000

200,000



© 2005 Tele Atlas


SR 522 BothellMilepost 10.9 to 12.72

SR 522 BothellLength: 1.82 milesMedian width: 40 feet Speed limit: 60 mph Barrier type: High-tensionYear installed: 2006

SR 522 Bothell No injury

Possible injury

Evidentinjury






!(

!(

Kenmore

Bothell

522 522

202

527

405

Lk. Washington

NS N O H O M I S HC O U N T Y

K I N GC O U N T Y

The cable median barrier generally is located 10 feet from the edge of the westbound lanes.


• A westbound vehicle traveled across the median and came to rest in the eastbound lanes without hitting another vehicle.



95 97 99 01 03 05 070

50,000

100,000

150,000

200,000



© 2005 Tele Atlas


SR 539 Ten Mile Road Milepost 6.07 to 8.13

SR 539 Ten Mile RoadLength: 2.06 milesMedian width: 76 feet Speed limit: 50 mph Barrier type: High-tensionYear installed: Late 2009

SR 539 Ten Mile Road No injury

Possible injury

Evidentinjury


All median collisions before (60 months) No Data

All median collisions after (0 months) No Data

Cross median collisions before (60 months) No Data

Cross median collisions after (0 months) No Data

This cable barrier installation is a portion of a widening project that is ongoing. Project completion is expected in late 2009.


95 97 99 01 03 05 070

50,000

100,000

150,000

200,000



Whatcom

NN

539

Bellingham

544

© 2005 Tele Atlas


Concrete median barrier


I-5 Lewis and Cowlitz countiesMilepost 51.09 to Milepost 85.29

I-5 Lewis and Cowlitz countiesLength: 34.20 milesMedian width: 15-40 feet Speed limit: 60-70 mph Year installed: 1997 or before*

I-5 Lewis/Cowlitz Counties No injury

Possible injury

Evidentinjury


All median collisions before No data


Cross median collisions before No data


* Barrier was installed in several contracts

Centralia

Chehalis

Napavine

Winlock

Vader

Toledo

5

507

6 508

122

12

505506

504

L E W I S C O U N T Y

C O W L I T ZC O U N T Y

N

70 mph60 mph

The concrete median barrier through this area generally is located in the center of the median.

Eighteen cross-median incidents have occurred in this section during the seven years studied:

• Ten collisions involved vehicles that crossed the median and hit other vehicles traveling in the opposite direction.

• Six of the collisions occurred between mileposts 82.65 and 84.27 an area that includes the Harrison Avenue interchange in Centralia.

• Thirteen of the collisions involved southbound vehicles traveling across the median.

Four fatal median-related crashes occurred in this section during the seven years studied:

• None of these collisions involved vehicles that crossed over the median.

• All of these collisions involved the concrete barrier; in one collision the vehicle rolled over after impact with the concrete barrier. In another, the driver was ejected.

A highway widening project between mileposts 72.39 and 76.15 resulted in significant modifications to traffic flow patterns to accommodate construction activities in the median. Collisions in this segment from July 9, 2007 through the end of 2008 were deemed non-typical and were excluded from the data.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


© 2005 Tele Atlas


I-5 Tacoma vicinityMilepost 116.81 to Milepost 130.70

I-5 Tacoma vicinityLength: 12.79 milesMedian width: 12-40 feet Speed limit: 60 mph Year installed: 1986

I-5 Tacoma vicinity No injury

Possible injury

Evidentinjury






5

5

705Tacoma

Steilacoom

DuPont

Fife

509

167

7

512

Puget SoundP I E R C E C O U N T Y

N

Fort Lewis

The concrete median barrier in this area generally is located in the center of the median.

Eight cross-median incidents have occurred in this section during the seven years studied:

• Three collisions involved vehicles that crossed the median and hit other vehicles traveling in the opposite direction.

• Two of the collisions occurred at milepost 122.58, in the vicinity of the Berkley Street Interchange.

• Three of the collisions occurred between milepost 129.57 and 129.92, an area which encompasses the 72nd and 84th Street interchanges.

• Six of the collisions involved southbound vehicles traveling across the median.

One fatal median related crash occurred in this section during the seven years studied. A northbound vehicle hit the concrete median barrier and the driver was ejected and killed.


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07

North ofFort Lewis

South ofFort Lewis


© 2005 Tele Atlas


I-5 Everett to MarysvilleMilepost 192.58 to 198.90

I-5 Everett to MarysvilleLength: 6.32 milesMedian width: 22 feet Speed limit: 60 mph Year installed: 2001

I-5 Everett to Marysville No injury

Possible injury

Evidentinjury






Marysville

5

5

526

525

529

52892

9

204

Lake Stevens

Snohomish

Everett

Mukilteo

Puget SoundLake Stevens

2

N

S N O H O M I S H C O U N T Y

Average Annual Daily Traffic VolumeVehicles per day by year

0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


One cross-median incident occurred in this section during the seven years studied.

• A southbound vehicle hit the barrier and went over into the northbound lanes where it hit a northbound vehicle.

Two fatal median-related crashes occurred in this section during the seven years studied.


© 2005 Tele Atlas


I-90 SpokaneMilepost 275.30 to 279.50

I-90 SpokaneLength: 4.20 milesMedian width: 22-40 feet Speed limit: 60-70 mph Year installed: 2004 or before

I-90 Spokane, Geiger Road to SR 2 No injury

Possible injury

Evidentinjury






290

2395

90

90

195

2

Spokane River

Spokane

N 70 mph60 mph


0

50,000

100,000

150,000

200,000


95 97 99 01 03 05 07


One cross-median incident occurred on the Geiger Road to US 2 portion during the four years studied.

• An eastbound vehicle first struck a sign on the right, then crossed all three lanes to strike and top the barrier.


I-90 Spokane, SR 2 to Latah Creek No injury

Possible injury

Evidentinjury






© 2005 Tele Atlas

cable median barrier€¦ · barrier, median barrier construction in marysville, and ongoing...

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