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July 2017

Supplement #1Travel Demand Modeling Report

Alabama 2040 Statewide Transportation Plan

Prepared byJ. R. Wilburn and Associates, Inc.

Prepared for

Alabama Department of TransportationBureau of Transportation Planning and Modal Programs

ALABAMA2040STATEWIDETRANSPORTATIONPLANSUPPLEMENT#1:TRAVELDEMANDMODELINGREPORT

July2017 Supplement#1-Pagei

TABLEOFCONTENTS

1. Introduction.............................................................................................................................1

2. TravelDemandModelingMethodology...................................................................................1

2.1 BaseYearZoneStructureandHighwayNetwork............................................................................1 Figure1:ZoneStructureUsingCensusTracts..........................................................................2 Figure2:StateRoadwaySystem..............................................................................................3 Figure3:ModelRoadwayNetwork..........................................................................................4

2.2 SocioeconomicDataAggregationandTripGeneration..................................................................5

2.3 FreightValues..................................................................................................................................5 Figure4:RoadwayNetworkAttributesforFreight..................................................................6

2.4 TravelDemandModelDevelopment,CalibrationandValidation..................................................6

2.5 PopulationandEmploymentProjections........................................................................................6

2.6 ModelingScenarios.........................................................................................................................7 Table1:MajorCapacityImprovementsCommittedThrough2040.........................................7 Figure5:MajorCapacityImprovementsCommittedThrough2040.......................................10

2.7 TestingthePerformanceoftheImprovementsProgram.............................................................11 Table2:ProjectedConditionsComparison–2040No-Buildvs.2040E+C.............................11 Table3:ProjectedCongestedSegmentsComparison–2040No-Buildvs.2040E+C............12

2.8 IssueswithModelMethdologyandUS280..................................................................................12

3. CapacityFundingGapAnalysis...............................................................................................13

3.1 DeterminingtheLane-MilesNeededtoAddressCongestion.......................................................13 Figure6:GapAnalysisUrbanAreas........................................................................................14 Table4:NumberofAdditionalLane-MilesNeededtoAddressCongestion...........................15

3.2 DevelopingCostEstimatestoConstructtheAdditionalLane-Miles.............................................15 Table5:CosttoConstructtheAdditionalLane-Miles............................................................16

3.3 GapinAvailableFundingtoMeetProjectedCapacityNeeds.......................................................16 Table6:ProjectedFundingforCapacityImprovements........................................................17

3.4 AlternativeUrbanScenarios..........................................................................................................17 Table7:NumberofAdditionalLane-MilesNeededtoAddressCongestion–

AlternativeUrbanScenario#1.................................................................................17 Table8:CosttoConstructtheAdditionalLane-Miles–AlternativeUrbanScenario#1........18 Table9:NumberofAdditionalLane-MilesNeededtoAddressCongestion–

AlternativeUrbanScenario#2.................................................................................19 Table10:CosttoConstructtheAdditionalLane-Miles–AlternativeUrbanScenario#2.......20

3.5 FundingNeededtoMaintainCurrentConditions.........................................................................20 Table11:TotalFundingRequiredThrough2040toMaintainConditionsat2010Levels

(V/Cat1.0)...............................................................................................................20


July2017 Supplement#1-Page1

1. Introduction

Alabama’s statewide travel demand model is an important tool for determining existing and futurecongestionlevels.Toprojectoveralltraveldemand,thetraveldemandmodelassignstripstoastatewidemodelroadwaynetworkbasedonexistingandprojectedsocioeconomicdatarelatedtopopulationandemployment.InurbanizedareasofthestatewitintheboundariesofaMetropolitanPlanningOrganization(MPO),thesocioeconomicdatafromtheMPO’straveldemandmodelisincorporatedintothestatewidemodelasappropriate.Theinformationderivedfromthestatewidemodeliskeytoidentifyingprojectedneedsanddevelopinganoverallstatewideinvestmentstrategy.

Thissupplementalreportpresentsthemethodologyandactivitiesundertakentoupdatethestatewidetraveldemandmodelasapartofthe2040updatetotheAlabamaStatewideTransportationPlan(SWTP)fortheAlabamaDepartmentofTransportation(ALDOT).Assuch,itprovidesadiscussionon:

• Developmentofthebaseyearzonestructureandhighwaynetwork• Processofaggregatingsocioeconomicdataanddevelopingtripgeneration• Integrationoffreightvaluesintothemodel• Traveldemandmodeldevelopment,calibrationandvalidation• Sourcesforpopulationandemploymentprojections• Modelingscenariostestedfortheplan• Methodologyandresultsfortestingtheperformanceofplannedimprovements

In addition, themodelwas used to conduct a funding gap analysis. The analysis compared identifiedcapacityneedsagainstprojectedfundingtodeterminetheshortfallinfundingforcapacityimprovementstoaddresscongestionneedsthrough2040.

2. TravelDemandModelingMethodology

2.1 BaseYearZoneStructureandHighwayNetwork

Thefirsttaskassociatedwiththetraveldemandmodelingeffortwastoupdatethezonestructureandroadwaynetworktoreflectthenewbaseyear.Thepreviousmodelused2005asthebaseyearfortheroadwayconditionsandthe2000CensusTractsasthebasisforthezonestructure.Theupdatedversionusesthe2010CensusTractsasthebaseyearzonestructureandeither2010or2015astheyearforthedataandroadwayestimates,dependingonthedataavailabilityandquality.

TheCensusTractnumbersforAlabamachangedbetweenthe2000and2010Census,withtheadditionofnearly100CensusTractsstatewide,bringingthetotalto1,179zones.ThisresultedintheneedtoupdatethezonestructureandcorrespondingcentroidconnectorplacementsacrossthestatetoallowfortheuseofallthenewCensusTracts.TheCensusTractlocationsweredownloadedfromtheCensuswebsiteinArcGISformatandthepopulationandhouseholdswereobtainedwiththedata.Figure1showsthezones.

Thestatewidemodel’sroadwaynetworkincludesInterstates,USroutes,andStateroutes,asshowninFigure2,andwasdevelopedthroughcoordinationbetweenALDOTandthestate’sMPOsandRegionalCouncils (RCs). The National Highway System (NHS) is an important roadway network componentmaintainedbyALDOTandisalsocontainedwithinthestatewidemodel.Wherenecessarytoallowforconnectivitybetweenroadwaylinksandcentroids,someadditionalroadwayswereinserted,primarilyinurbanareas.Themodelnetwork,showninFigure3,alsoincludesroadwaysneededforconnectivity.



Figure1:ZoneStructureUsingCensusTracts



Figure2:StateRoadwaySystem



Figure3:ModelRoadwayNetwork



ItshouldbenotedthattheurbanizedareaMPOmodelspresentinformationatafinerlevelofdetailthanthestatewidetraveldemandmodel. ThisisarrivedatbysplittingthelargerCensusTractbasedzonesintosmaller,morenumerousTAZ(trafficanalysiszones).This isappropriatetotheirregionalplanningneedsastheMPOmodelsaredesignedtoassessregionalcharacteristicsofaparticularurbanizedarearatherthanatastatewidelevel.

Themodelnetworkisattributedwithdistance,postedspeedlimit,numberoflanes,traveltime,averagedailytraffic,percenttrucks,androadwaynames.ThedistancewasobtainedfromCUBEvoyagersoftwarewhenthenetworkwasdigitized.ThepostedspeedlimitandnumberoflaneswereobtainedusingtheState’sCAREcrashdatabase,inwhichcrashesareattributedwiththesevaluesbytheofficersinspectingthecrashesforcrashanalysis.TrafficandpercenttrucksweretakenfromadatabaseprovidedbyALDOT,whiletraveltimewascalculatedusingtheprogram.

2.2 SocioeconomicDataAggregationandTripGeneration

ThesocioeconomicdatawascollectedusingtheUSCensuspopulationandhouseholdnumbersfor2010and the Longitudinal Employer-Household Dynamics data set available from the US Census for theemployment data. The data collected included the number of households, average income for thehouseholds,retailemploymentandnon-retailemployment.

Theexternalcountdatawerecollectedfromthestatewidetrafficcountdatabaseatthestatelinetoallowfortheexternaltrafficnumbers.Theexternalroadtype,takenfromfunctionalclassification,wasusedtodeterminethepercentpass-throughtripsat theexternal location.Thepercentagesused inthemodelwerethesameasthoseusedinthepreviousstatewidemodeltoremainconsistent.

TheAlabamaTripGenerationprogramwasrunforthedatacollected.Theresultsincludedthenumberofproductionsandattractionsexpectedforeachzoneandexternalstationforthesixdifferenttrippurposes:home-based-work, home-based-other, non-home-based, truck-taxi, external-internal, and external-external.

2.3 FreightValues

Thefreightvaluesforthemodelroadwayswerecollectedfromthestate.Theprocessusedthecountedtruck percent for each roadway. The freight flows and truck percentages were compared to ensurecompatibilitylaterintheupdateprocess.Aspatialjoinwasperformedtoattributetheroadwaysinthemodelwiththeappropriatetruckpercentfromthestatewidedatabase.Anexampleforoneparticularlocationinthecentralwesternportionofthestate(designatedbytheredcircles)isshowninFigure4.



Figure4:RoadwayNetworkAttributesforFreight

2.4 TravelDemandModelDevelopment,CalibrationandValidation

ThetraveldemandmodelwasdevelopedinCUBEVoyagerformat.Theprocessusedtheroadwaynetworkand results from the tripgenerationprogramas inputs to themodel.The steps in themodelprocessincluded tripdistributionand trafficassignment;asavehicle-onlymodel, therewerenoothermodesmodeledintheprocess.ThemodelinCUBEVoyagerconsistsofacollectionofmodulesthatconvertthemodelintoassignedtrafficvolumes.

The calibration and validation of the travel demand model was performed using the Validation andReasonablenessCheckingManual.Initialvalidationstatisticsweredeveloped.Themodelwastestedusingthe statistical parameters identified, and the values were tested to ensure they met the thresholdsidentified.

2.5 PopulationandEmploymentProjections

Thedistributionofpopulationandemploymentacrossthestateisakeycomponenttothetraveldemandmodel.Socioeconomic(SE)dataforthestatewidetraveldemandmodelwasobtainedforbaseyear2010andtheforecastyear2040.Thebaseyear2010SEdatawereobtainedfromtheUSCensusBureauandincluded households, household income, and employment (retail and non-retail). Forecast year 2040



projectedhouseholdandemploymentvaluesweredevelopedusingdatafromtheMPOs(forurbanareasonly)andtheUniversityofAlabamaCenterforBusinessandEconomicResearch(CBER).Countygrowthpercentageswereappliedtoeachtrafficanalysiszone(TAZ)inthestatewidemodel.Intheurbanareas,thegrowthpercentageswerematchedwiththeMPO’sprojectedgrowthonapercentagebasistoallowforadditionalrefinementbasedontheavailabilityofmoredetailedlocaldataandinput.

2.6 ModelingScenarios

Threescenariosweredevelopedforthemodelingprocess:• Baseyear2010modelwith2010SEdataandnetwork.Thismodelrunreflectsexistingcongestion

andcapacityneeds.• Futureyear2040No-BuildAlternative,withthe2010networkand2040SEdata.Thismodelrun

reflectsthebaselineforfuturecapacityneeds.• Future year 2040with existing and committed (E+C) projects and 2040 SE data. This reflects

capacityneedsremainingafterconstructionofcapacityimprovementsthrough2040.

Thecommittedprojectsthroughyear2040incorporatedintheE+CmodelingscenarioincludethemajorcapacityimprovoementsintheALDOTworkprogramasofApril1,2017.TheseprojectsarelistedinTable1andshowninFigure1.

Table1:MajorCapacityImprovementsCommittedThrough2040

MapID Description(PlannedConstructionYearsinParentheses)

1 Widening of US 72 from Indian Springs Road to East of Harris Road from 4 to 7 lanes inLauderdaleCounty(2027)

2 WideningofUS72Eastof the intersectionofCR-528 (JeffersonStreet) tobeneath theCSXrailroadfrom4to6lanesinLimestoneCounty(2019)

3 WideningofUS72fromCountyLineRoadtoProvidenceMainfrom4to6lanesinMadisonCounty(2019)

4 WideningofSR53fromNorthofTaurusLanetoHarvestRoadfrom2to5lanesinMadisonCounty(2024)

5a WideningofMemorialParkway (US231) fromSouthofCR75 (MastinLakeRoad) toCR65(WinchesterRoad)from4to8lanesinMadisonCounty(2018)

5b WideningofMemorialParkway (US231) fromLakewoodDrive toHollowRoad from4 to6lanesinMadisonCounty(2038)

6 WideningofSR35 fromWilliamStreet to theTennesseeRiver from2to4 lanes in JacksonCounty(2021)

7 RelocationofSR69fromUS231toMainStreet inArabtoanew5-lanefacility inMarshallCounty(2023)

8a WideningofSR157fromSR69toUS31from2to5lanesinCullmanCounty(2020)

8b WideningofSR69from4thAvenuetoUS278from2to4lanesinCullmanCounty(2026)

9 WideningofSR13inHaleyvillefrom2to3lanesinWinstonCounty

10 WideningofSR13fromWalkerCounty linetoUS278from2to4 lanes inWinstonCounty(2022)

11 WideningofI-65fromBlountCountylinetosouthofSR69from4to6lanesinCullmanCounty(2025)




12 ConstructionofBirminghamNorthernBeltline,anew6-lane facility fromSR79 toSR75 inJeffersonCounty(2036)

13a WideningofSR-77fromI-59toUS11from2to5lanesinEtowahCounty(2022)

13b WideningofSR-77fromUS11toUS431from2to3lanesinEtowahCounty(2025)

14 WideningofSR200fromSR21toUS278from2to4lanesinCalhounCounty(2030)

15 WideningofUS231fromCropwellRoadtoSR34from2to5lanesinSt.ClairCounty(2020)

16 WideningofI-59fromI-459toChalkvilleMountainRoadfrom4to6lanesinJeffersonCounty(2022)

17 ConstructionofI-22asa4-lanefacilityfromI-65toUS31inJeffersonCounty(2025)

18 WideningofUS78fromFinleyBoulevardtoPrattHighwayfrom5to7lanesinJeffersonCounty(2027)

19a WideningofI-59fromUS11(1stAvenueNorth)toI-459from4to6lanesinJeffersonCounty(2023)

19b WideningofI-59from18th/19thStreet(Exit112)toValleyRoad(Exit118)from4to6lanesinJeffersonCounty(2025)

20 WideningofUS280overI-459fromSummitBoulevardtoBlueLakeDrivefrom2to3lanesinJeffersonCounty(2022)

21 WideningofSR150fromParkwoodDrivetowestofShadesCreekfrom2to4lanesinJeffersonCounty(2020)

22 Constructionofa4-laneHelenaBypassfromCR52westofHelenatoSR261northofHelenainShelbyCounty(2022)

23 WideningofSR261fromBeardenRoadtoUS31from2to5lanesinShelbyCounty(2020)

24 WideningofSR119fromCR80toCR26from2to4lanesinShelbyCounty(2017)

25 WideningofI-65fromUS31toCR52from4to8lanesinShelbyCounty(2021)

26 Constructionofa4-laneCaleraBypassfromSR25westofCaleratoUS31northofHelenainShelbyCounty(2022)

27 Bridgewideningson I-65 fromExit 228 toExit 231nearCalera from4 to6 lanes in ShelbyCounty(2022)

28 WideningofUS82fromwestofGordotoTuscaloosaCountylinefrom2to4lanesinPickensCounty(2019)

29a Widening of US 11 from Lower Coaling Road to Haglar Coaling Road from 2 to 3 lanes inTuscaloosaCounty(2023)

29b WideningofUS11fromI-59toKeppleLoopRoadfrom2to3lanesinTuscaloosaCounty(2033)

30 WideningofSR215fromSR216toUS11from2to4lanesinTuscaloosaCounty(2019)

31 WideningofI-59fromBlackWarriorParkwaytosouthofButtermilkRoadfrom4to6lanesinTuscaloosaCounty(2017,2018)

32 New2-lanesegmentofSR22from(Roanoke)MainStreettoUS431inRandolphCounty(2020)

33 WideningofSR21fromSylacaugatoCR213from2to4lanesinTalladegaCounty(2030,2031)

34 Relocationof2-laneSR77fromCR35toCR31inClayCounty(2017)

35 WideningofUS31atI-65inClantonfrom2to3lanesinChiltonCounty(2018)

36 WideningofSR22from2to4lanesinDallasCounty(2021)

37 WideningofUS82fromSR14toUS31from2to4lanesinAutaugaCounty(2023)




38a WideningofSR14fromIngramRoadtoCoosadaParkwayfrom2to4lanesinElmoreCounty(2019)

38b WideningofSR14fromLucytownRoadtoCallowayCreekfrom2to4lanesinElmoreCounty(2021)

39 Extensionof2-laneserviceroadsalongNorthernBoulevardinMontgomeryCounty(2025)

40 WideningofSR110fromVaughnRoadtoproposedOuterLooplocationfrom2to5lanesinMontgomeryCounty(2021)

41 WideningofI-85fromTaylorRoadtoJenkinsCreek(eastofChantillyParkway)from4to6lanesinMontgomeryCounty(2030)

42 ExtensionofaccelerationlanesalongI-85atExits26,38,and42inMaconCounty(2018)

43 WideningofI-85fromMilePost58.6toMilePost62.45from4to6lanesinLeeCounty(2030)

44 AdditionofatruckclimbinglaneonSR21atFalkenberryHillinMonroeCounty(2025)

45 WideningofUS84fromMonroeCountytoI-65from2to4lanesinConecuhCounty(2030-2032)

46 WideningofUS331fromCR17toCR5from2to4lanesinCrenshawCounty(2023)

47 WideningofSR167fromUS84tonorthofSalemRoad from2to5 lanes inCoffeeCounty(2026)

48a WideningofRossClarkCirclefromBaumanDrivetoCherokeeAvenuefrom4to6lanes(2018)

48b WideningofRossClarkCirclefromUS231SouthtoBaumanDrivefrom4to6lanes(2028)

49a WideningofUS98fromMississippiStateLineto0.5mileeastofGlenwoodRoadfrom2to4lanesinMobileCounty(2019)

49b SR158Extensionas4-lanefacilityfromGlenwoodRoadtoSchillengerRoadinMobileCounty(2017-2026)

49c WideningofSR158fromI-65toUS43from2to4lanesinMobileCounty(2025)

50 WideningofI-10fromCR39toCarolPlantationRoadform4to6lanesinMobileCounty(2023)

51 WideningofUS90fromCR39to4-lanesegmentsouthofTheodorefrom4to6lanesinMobileCounty(2031)

52a WideningofI-10andbridgesfromBroadStreettotheMobileCountyLinefrom4to8lanesinMobileCounty(2020)

52b WideningofI-10andbridgesfromtheMobileCountyLinetoUS90from4to8lanesinBaldwinCounty(2020)

52c WideningofI-10fromeastoftheBaywayBridgetoeastofSR181from4to6lanesinBaldwinCounty(2020)

53 WideningofUS31fromSpanishForttoSR181from2to5lanesinBaldwinCounty(2017)

54a WideningofSR181fromSR104toCR64from2to5lanesinBaldwinCounty(2017)

54b WideningofSR181fromUS98toSR104from2to4lanesinBaldwinCounty(2023,2024)

55 WideningofSR180fromSR59toSR161from2to4lanesinBaldwinCounty(2021,2022)



Figure5:MajorCapacityImprovementsCommittedThrough2040

Florida

Georgia

MississippiTennessee Tennessee

Georgia

Lillian

Greenville

Selma

Albertville

Guntersville

Grove Hill

Phenix City

OpelikaAuburn

Prattville

Montgomery

Troy

Dothan

EnterpriseAndalusia

CenturyFlomaton

Orange Beach

Fairhope

DaphneMobile

Demopolis

Tuscaloosa

Birmingham

Jasper

Anniston

Gadsden

Muscle Shoals

Florence

Cullman

Hartselle

Decatur

HuntsvilleMadisonAthens

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£¤5

£¤431

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£¤280

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£¤98

£¤45

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£¤84

£¤84

£¤84

£¤231

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£¤72

£¤278

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0 20 40 60 8010Miles

®

06-06-2017

Source: Alabama Department of Transportation

E+C Projects based on JRWA Listing

Key Projects

! Planned Projects

Urban Boundary

2726

23

16

21

1817

1922

20

24

25

36

47

46

45

44

48

50

53

54

55

49 51

434241

4039

3837

30

29

1534

33 32

35

2831

9

1011

12

5

6

78

1413

4321



2.7 TestingthePerformanceoftheImprovementsProgram

Akeybenchmarkofanyimprovementprogrammeasurestheoverallbenefitsoftheprojectswithinthework program. This task utilized the statewide travel demandmodel to compare the base year 2010conditionstoprojectedconditionsunderthe2040No-Buildand2040E+Cscenarios.Itshouldbenotedthatthisanalysiswasconductedforthemajorroadwaysincludedinthemodelnetworkandthereforedidnotincludeanycountyorlocalroads,someofwhichcarrysignificantvolumes,particularlyinurbanareas.

Table2presentstheconditionsundereachofthethreemodelingscenarios.Inadditiontosocioeconomicdatarelatedtopopulationandemployment,threeadditionalfactorswerecompared:

• VehicleMilesTraveled(VMT)–Milestraveledbyallvehiclesontheroadwaynetworkinagivenyear.Thisisagoodmeasureoftheoverallutilizationofthenetwork.

• VehicleHoursTraveled(VHT)–Hoursspenttravelingbyallvehiclesontheroadwaynetworkinagivenyear.Thisisagoodindicatorofoveralldelaywhencomparedtodifferentscenarios.

• Truck VMT – Miles traveled by trucks in a given year. This is good reflection of the overallutilizationoftheroadwaynetworkbytruckfreight.

Table2:ProjectedConditionsComparison–2040No-Buildvs.2040E+C

Severalkeyobservationsoftheanalysisinclude:• A16percentincreaseinVMTisprojectedunderthe2040No-Buildscenario,risingto25percent,

orapproximately561millionmilesof travel,under theE+C scenario.ConstructionofplannedimprovementsundertheE+Cscenarioareprojectedtoresultinanadditional38millionmilesoftravelcomparedtotheNo-Buildscenario.

• A113percentincreaseinVHT,toalmost126millionhoursoftravel,isprojectedunderthe2040No-Buildscenario.Incontrast,theincreaseundertheE+Cscenarioisless,at78percentoratotalof approximately 105 million hours. This reflects an overall reduction of 21 million hours incongestionrelateddelaythroughoutthestatewiththeplannedimprovements.

• WhencomparingVMTtoVHT,theratioofmilestraveledtohourstraveledreducessignificantlyunderboth theNo-Build andE+C scenarios. This indicates a significant increase in congestionstatewidethrough2040regardlessofimprovements.

• Aswithoveralltraffic,reducedcongestionduetoimprovementsthrough2040willresultinmoretruckmiles traveled throughout the state. Increases in truck travel indicate amore favorableenvironmentforeconomicdevelopment.

2010Base 2040No-Build 2040E+CHouseholds 1,883,791 2,110,572 2,110,572Population 4,803,667 5,381,960 5,381,960Employment 1,844,995 3,250,061 3,250,061Emp/HHRatio 0.979 1.540 1.540

VMT 450,554,946 523,328,110 560,947,038VHT 58,816,469 125,770,826 104,653,242VMT/VHT 7.7 4.2 5.4TruckVMT 97,382,214 114,057,538 122,470,824



Aspreviouslynoted,congestionthroughoutthestatein2040isprojectedtoincreaseunderbothfuturescenarios.Astandardmeasureofcongestion,LevelofService (LOS) isa functionof travel speedsanddelay.ItisorganizedonanAtoFgradingscaleinaccordancewiththesegeneraldescriptions:

• LOSA-C:Littletonocongestion• LOSD:Mildlycongested• LOSE:Atcapacityandcongested• LOSF:Over-capacityandheavilycongested

Table3compareslevelsofserviceforeachofthethreescenarios,asderivedfromthestatewidetraveldemandmodel. Under projected 2040 conditions, the totalmiles in each category and their relativedistributionsaresimilarbetweentheNo-BuildandE+Cscenarios.Approximately16percentofthestate’smajor roadways are projected to operate under LOS F conditions in 2040, evenwith the addition ofplannedcapacityimprovements.Thisindicatesthat:

• Thecapacityaddedbytheimprovementsthrough2040willbeabsorbedbyadditionaltripsthatresultfromtheincreasedconvenience.

• GiventheincreasedtravelyetreduceddelayprojectedundertheE+Cscenario(asseeninTable1), the severity of congestion on LOS F segmentswill be less, even if the number ofmiles ofcongestedsegmentsisprojectedtoremainmoreorlesscomparable.

Table3:ProjectedCongestedSegmentsComparison–2040No-Buildvs.2040E+C

2.8 IssueswithModelMethodologyandUS280

OneissueidentifiedduringthestatewidemodelingprocessrelatestothehightrafficvolumesbetweenAuburn,ALandColumbus,GAonUS280.Afunctionofhowtraveldemandmodelsoperate,thisparticularissueoccursbecausethetravelsituationbetweenPhenixCity,ALandColumbus,GAviolatestraditionalmodeling practice. Essentially, themodel attempts to use external traffic originating from householdlocationsanddistribute it towardzoneswithhighemployment.Fromthemodelperspective,externaltripsoriginatinginColumbus(households)aredestinedforemploymentortopurchasegoodsandservicesinthehigh-employmentlocationsinAuburn.However,inactuality,thetripsthatoccurinthisareatravelfromPhenixCity(householdorigins)intoColumbus(employmentdestinations),notAuburn.Thisresultsinthemodelassigningmoretripsthanoccurinactuality.

Miles % Miles % Miles %LOSA-C 103,594 78.1% 99,482 75.0% 99,977 75.3%LOSD 6,353 4.8% 6,000 4.5% 6,044 4.6%LOSE 5,306 4.0% 4,995 3.8% 5,016 3.8%LOSF 17,335 13.1% 22,111 16.7% 21,765 16.4%

2010(Existing) 2040(No-Build) 2040(E+C)



3. CapacityFundingGapAnalysis

ThecongestedlocationsandconditionscurrentlyexperiencedonAlabama’sState-maintainednetworkare projected to continue increasing statewide through 2040, evenwith the construction of plannedprojects. An analysis of the funding “gap” between projected revenues and the financial investmentneeded to provide for relatively uncongested conditions across the entire network (and thus avoidworseningcongestionatmore locations)wascompleted.Theanalysisconsideredtwoprimaryfactors:thenumberoflane-milesofcongestedfacilities,andthecostofcapacityimprovements.Thederivedcostwasbasedonhigh-levelcostestimatesper lane-mileusinghistoric informationfromALDOTincurrentdollars.Thecongestionlevelswerederivedfromtwotraveldemandmodelruns:

• BaseYear(2010)–todeterminecurrentcongestionlevels• ExistingplusCommitted(E+C)(2040)–todeterminefuturecongestionlevels

Thegapanalysismethodologyconsistedoffoursteps:1. Identifythenumberofadditionallane-milesofcapacitynecessarytoalleviatecongestion.Lane-

mileswerenotedbyareatype(urbanorrural)andfacilitytype(freewayorarterial).2. Develop an estimated total cost per lane-mile for capacity improvements based on ALDOT

standardsandhistoricalinformation.3. Calculatethetotalcosttoaddcapacitytoallidentifiedlane-milesofneed.4. Compare the cost of the identified capacity investments against the projected revenues to

determinethefundinggap.

Itshouldbenotedthatthis isamacro-levelstatewideanalysistodeterminecapacityneeds.Inreality,manyofthesecongestedcorridorsmaynotbesuitableforwideningprojectsduetocorridorconstraintsthatwouldbedeterminedthroughamoredetailedcorridoranalysisduringprojectdevelopment.Givencorridor constraints, other improvements such as signal enhancements, turn lane modifications, orimprovementstoparallelfacilitiesmaybeappropriate.

3.1 DeterminingtheLane-MilesNeededtoAddressCongestion

Theroadwaynetworkandcongestiondatawasderivedfromthetraveldemandmodel.Adailyvolume-to-capacity(V/C)ratioof1.0wasdeterminedasthethresholdforacceptablecongestion.Foreachgivenfacilityinthetraveldemandmodelnetwork,thetrafficvolumesweresubtractedfromthefacilitycapacitytodeterminethenumberofexcesstrips.Then,thenumberofadditional lanesneededtoservetheseexcess trips, and thereby bring the roadway within the volume-to-capacity threshold of 1.0, wasdetermined.Thenumberofadditionallaneswasmultipliedbythelengthofthesegmenttoderivethetotalnumberoflane-milesforagivenfacility.Theresultinglane-milesneededalongtheentirenetworkwereaddedtogethertodeterminethestatewidetotalofneededlane-miles.Itshouldbenotedthatthisanalysiswasconductedbydirectional lane-milesandnotcenterlinemiles.Withinanygivencenterlinemile,aneedformultiplelanemilestoaccommodateadditionalcongestiononbothdirectionswouldbeneeded.Theactuallengthofdeficientsegmentscollectivelyrepresentsthenumberofdeficientcenterlinemilesthroughoutthestate.

Thecongestedroadwaylane-mileswerecategorizedbylocation(urbanorrural)andfacilitytype(freewayorarterial)duetothedifferencesinherentintheirconstructioncosts.Forthepurposesofthisanalysis,



roadwayswithinfivecountieswerecategorizedasurban:Jefferson,Madison,Mobile,MontgomeryandShelby,asshowninFigure6.

Figure6:GapAnalysisUrbanAreas



TheanalysisresultsindicatethatsignificantinvestmentsinadditionalcapacitywouldberequiredtoalleviateexistingcongestionacrossAlabama.AsTable4shows,morethan11,800lane-milesofadditionalcapacityisneededtoaddresscurrentcongestion.Evenwiththeconstructionofplannedcapacityimprovementsthrough2040,thiswillincreasetomorethan13,200lane-milesby2040.Theneedforadditionallane-milesissignificantlygreateronarterialfacilitiesinbothurbanandrurallocationsthanforfreewaysunderbothcurrentandfutureconditions.

Table4:NumberofAdditionalLane-MilesNeededtoAddressCongestion

Giventheextensiveneedsinadditionallane-milesofcapacityindicatedbythisanalysis,itisimportanttoconsiderthegrowthinneededlane-milesbetweennowto2040.AsshowninTable3,approximately1,400lane-milesofadditionalcapacitywouldberequiredby2040tosimplymaintaincurrentconditionsandmitigateworseningcongestion.

3.2 DevelopingCostEstimatestoConstructtheAdditionalLane-Miles

UnitcostsfromALDOT(basedonhistoricalinformation)wereusedtodevelopestimatedperlane-milecostsbyfacilitytypeandlocation.Thenotablyhighercostforurbanimprovementsisattributabletoanumber of factors, including increased costs for right-of-way acquisition, utilities relocation, and theasphaltpavementdensitiesnecessitatedbygreater trafficvolumes.Theestimatedcostperadditionallane-milebyfacilitylocationandtypeis:

• UrbanFreeway $5,301,455• UrbanArterial $4,348,185• RuralFreeway $3,191,455• RuralArterial $2,238,185

Table5presentsabreakdownofthetotalinvestmentcost(incurrentdollars)requiredtoconstructtheadditional lane-milesofneededcapacity identified inTable2. The cost toaddress current congestionneedstotalsapproximately$40.5billion.Thetotalneedjumpsto$45.7billionby2040,evenaftertheconstructionofplannedimprovementsintheALDOTworkprogram.Thelargerportionofcostsallocatedtoarterialfacilities(approximately85percent)correspondstothesignificantlygreaterneedforlane-milesalongthestate’sarterialfacilities.Similarly,giventhatperlane-milecapacityimprovementsinurbanareascostsubstantiallymorethanthoseinruralareas,itisnotunexpectedthatmoreofthespendingwouldbeusedforfacilitiesinurbanareas.Urbanareafacilitiesaccountforapproximatelytwo-thirdsoftotalcosts.

FacilityType 2010BaseYear 2040E+C DifferenceUrbanFreeway 814 1,003 189UrbanArterial 5,340 5,894 554RuralFreeway 208 520 312RuralArterial 5,492 5,851 359TOTAL 11,854 13,268 1,414



Table5:CosttoConstructtheAdditionalLane-Miles

The cost to respondonly toworsening congestionbetween2010 and2040 totals $5.2 billion for theapproximately1,400lane-milesofadditionalcapacityindicatedinTable4.Thelargestportion(nearlyhalf,or$2.4billion)wouldbeallocatedtourbanarterialfacilities.

3.3 GapinAvailableFundingtoMeetProjectedCapacityNeeds

AnydiscussionofALDOTfundingexpendituresmustbeprecededbynotingthataforemostpriorityoftheDepartment is on maintaining previous infrastructure investments. Therefore, maintenance projects(includingresurfacing)account forasignificantportionofALDOT’sexpenditures,andareprojectedtocontinuetodosothrough2040.Furthermore,theexactprogrammingofmaintenancefundstospecificprojects cannot be done more than several years in advance given the shorter-term nature ofmaintenanceneedsandprojecttypes.

BasedoninformationprovidedbyALDOTfor2017-2020fundingandexpenditures,roughly7percentofavailablefundingrevenues,or$391million,isprojectedtobespentoncapacityimprovements.Toextendrevenueandexpenditureprojectionstotheyears2021-2040,thefollowingstepsweretaken:

1. Atwopercentannualinflationratewasappliedtotheamountoffederalfundingthrough2040.ThisisconsistentwiththeinflationrateprovidedbyFHWAfortheFASTAct.

2. Statefundingwasincreasedby$5millionannuallythrough2040,aswasassumedintheshort-termprojectionsthroughtheFASTActprovidedbyALDOT.

3. The same distribution of expenses for capacity improvements provided in the short-termprojectionsbyALDOT(7percent)wasassumedtoremainconstantfrom2021through2040,asshowninTable6.

FacilityType

CenterlineMilesofNeeded

ImprovementsLaneMilesof

CapacityNeeded

ImprovementCostperLane-Mile(Current$)

TotalCostforImprovements

UrbanFreeway 346 814 $5,301,455 $4,315,384,000UrbanArterial 1,464 5,340 $4,348,185 $23,219,310,000RuralFreeway 86 208 $3,191,455 $663,823,000RuralArterial 2,200 5,492 $2,238,185 $12,292,114,000TOTAL 4,096 11,854 N/A $40,490,631,000

FacilityType


ImprovementsLaneMilesof

CapacityNeeded



UrbanFreeway 393 1,003 $5,301,455 $5,317,359,000UrbanArterial 1,453 5,894 $4,348,185 $25,628,205,000RuralFreeway 234 520 $3,191,455 $1,659,556,000RuralArterial 2,850 5,851 $2,238,185 $13,095,623,000TOTAL 4,929 13,268 N/A $45,700,743,000

2010BaseYearNeededCosts

2040E+CNeededCosts



AsTable6shows,ALDOTisprojectedtohaveover$2.6billionforcapacityimprovementsthrough2040.

Table6:ProjectedFundingforCapacityImprovements

Given the funding projections, the $2.6 billion available for capacity improvements through 2040 is$37.8billionlessthanwhatisneededtoalleviatecurrentcongestionneeds($40.5billion).Whileplannedimprovementsthrough2040willhelpaddresscongestionneeds,approximately$45.7billioninadditionalcapacityimprovementsisneededtoalleviateprojectedcongestion.

3.4 AlternativeUrbanScenarios

Given thatmosturbanareas areprojected tohavemore severe levelsof congestion, twoalternativeanalysesweredeveloped:

• AlternativeUrbanScenario#1–thatincreasedacceptableV/Cratiosto1.15inurbanareaswhilemaintainingaV/Cof1.0inruralareas.

• AlternativeUrbanScenario#2–thatincreasedacceptableV/Cratiosto1.30inurbanareaswhilemaintainingaV/Cof1.0inruralareas.

AlternativeUrbanScenario#1Analysis

AsTable7shows,byincreasingacceptableV/Cratiosto1.15inurbanareas,thenumberoflane-milesneededtoalleviateexistingcongestionunderthisscenariodropsslightlytoapproximately11,300lane-miles(versus11,800lane-miles intheoriginalscenario).Similarly,areductionisprojectedinthelane-miles needed to address congestion in 2040, decreasing to approximately 12,900 lane-miles underAlternativeUrbanScenario#1(versus13,200lane-milesintheoriginalscenario).

Table7:NumberofAdditionalLane-MilesNeededtoAddressCongestion–AlternativeUrbanScenario#1

Itshouldbenotedthat,eventhoughthetotallane-milesofcongestiondecreasesinboth2010and2040whenusingthehigherV/Cthresholdof1.15,thenumberofadditionallane-milesthatmustbeimprovedby2040tomaintaincurrentconditionsactuallyincreasesunderthealternativeurbanscenario.ShowninTables4and7asthe“difference”inlane-milesbetween2010and2040,theoriginalscenarioresultedina total of an additional 1,414 lane-miles as compared to 1,569 lane-miles under Alternative UrbanScenario#1.Thisgreaterdifferenceresultsbecausemoreroadwaysarein1.0-1.15V/Crangein2010thanin2040.WhenthethresholdisincreasedtoaV/Cof1.15,asignificantnumberoflane-milesareremovedinthe2010scenario;however,fewerlane-milesfallwithinthe1.0-1.15V/Crangein2040.Essentially,

2017-2020 391,473,000$2021-2040 2,251,242,558$TOTAL 2,642,715,558$

FacilityType 2010BaseYear 2040E+C DifferenceUrbanFreeway 621 896 275UrbanArterial 4,974 5,597 623RuralFreeway 208 520 312RuralArterial 5,492 5,851 359TOTAL 11,295 12,864 1,569



therearealargenumberofmilesbetween1.0and1.15in2010,butnotasmanywithinthatrangein2040,sothereductionissmaller.Statedanotherway,theproportionofroadwaysonlyslightlycongested(1.0-1.15V/C)isgreaterin2010than2040,andconverselytheproportionofroadwayswithmoreseverecongestion (V/Cgreater than1.15) is greater in2040 than2010. Specifically,underAlternativeUrbanScenario#1,thetotallane-milesoverthethresholddecreasesby559in2010(11,854vs.11,295)andby404in2040(13,268vs.12,864),resultinginanetdifferenceof155lane-miles(559vs.404).

Table8presentsabreakdownofthetotalinvestmentcost(incurrentdollars)requiredtoconstructtheadditionallane-milesofneededcapacityunderAlternativeUrbanScenario#1.Thecosttoaddresscurrentcongestionneedsdecreases$2.6billiontoapproximately$37.9billion.Similarly,thetotalneedin2040decreasesbyroughly$1.9billiontoapproximately$43.8billion.Thelargerallocationofcoststoarterialsandurbanareas remainsunderAlternativeUrbanScenario#1.Similarly, theurban/rural split remainsconstant,withtwo-thirdsofexpendituresgoingtofacilitiesinurbanareas.

Table8:CosttoConstructtheAdditionalLane-Miles–AlternativeUrbanScenario#1

The cost to respond only to worsening congestion between 2010 and 2040 under Alternative UrbanScenario#1totals$6.0billion for the1,569 lane-milesofadditionalcapacity indicated inTable7.Thiscorrespondstoanadditional$756millionbeyondtheoriginalscenario.Again,thelargestportion(nearlyhalf,or$2.7billion)wouldbeallocatedtourbanarterialfacilities.Together,theurbanfreewayandarterialfacilitieswouldstillamountforroughlytwo-thirdsofthecosts.

FacilityType


Improvements

MilesofCapacityNeeded




FacilityType


Improvements




UrbanFreeway 339 896 $5,301,455 $4,750,103,000UrbanArterial 1,305 5,597 $4,348,185 $24,336,794,000RuralFreeway 234 520 $3,191,455 $1,659,556,000RuralArterial 2,850 5,851 $2,238,185 $13,095,623,000TOTAL 4,727 12,864 N/A $43,842,076,000


2040E+CNeededCosts



AlternativeUrbanScenario#2Analysis

AsTable9shows,thenumberoflane-milesneededtoalleviateexistingcongestionunderthisscenariodropstoapproximately10,700lane-miles(versus11,800lane-milesintheoriginalscenario).Areductionisprojectedinthelane-milesneededtoaddresscongestionin2040,decreasingtoapproximately12,400lane-milesunderAlternativeUrbanScenario#2(versus13,200lane-milesintheoriginalscenario).

Table9:NumberofAdditionalLane-MilesNeededtoAddressCongestion–AlternativeUrbanScenario#2

As is the casewith AlternativeUrban Scenario #1, the number of additional lane-miles thatmust beimprovedby2040tomaintaincurrentconditionsalsoincreasesundertheAlternativeUrbanScenario#2whenusingthehigherV/Cthresholdof1.30.ShowninTables4and9asthe“difference”inlane-milesbetween2010 and2040, theoriginal scenario resulted in a total of an additional 1,414 lane-miles ascomparedto1,661lane-milesunderAlternativeUrbanScenario#2.AsisthecasewithUrbanScenario#1,thisgreaterdifferenceresultsbecausemoreroadwaysarein1.0-1.3V/Crangein2010thanin2040.Specifically,underAlternativeUrbanScenario#2,thetotal lane-milesoverthethresholddecreasesby1,074in2010(11,854vs.10,780)andby827in2040(13,268vs.12,441),resultinginanetdifferenceof247lane-miles(1,074vs.827).

Table10presentsabreakdownofthetotalinvestmentcost(incurrentdollars)requiredtoconstructtheadditionallane-milesofneededcapacityunderAlternativeUrbanScenario#2.Thecosttoaddresscurrentcongestionneedsdecreasesbyapproximately$5billiontoapproximately$35.5billion.Similarly,thetotalneedin2040decreasesbyroughly$3.8billiontoapproximately$41.9billion.ThelargerallocationofcoststoarterialsandurbanareasstillremainsunderAlternativeUrbanScenario#2.Similarly,theurban/ruralsplitremainsconstant,withtwo-thirdsofexpendituresgoingtofacilitiesinurbanareas.

FacilityType 2010BaseYear 2040E+C DifferenceUrbanFreeway 462 741 279UrbanArterial 4,618 5,329 711RuralFreeway 208 520 312RuralArterial 5,492 5,851 359TOTAL 10,780 12,441 1,661



Table10:CosttoConstructtheAdditionalLane-Miles–AlternativeUrbanScenario#2

3.5 FundingNeededtoMaintainCurrentConditions

Projections in Table 6 indicated that ALDOT is estimated to have a total of $2.6 billion for capacityimprovementsthrough2040.Furthermore,itisassumedthatallavailablefundingforplannedprojectsincludedinthe2040E+Cwouldbecompletelyexpended.Giventhesefactors,andassumingtheoriginal1.0 V/C threshold scenario, ALDOT would need approximately $7.8 billion through 2040 tomaintainconditionsat2010levels,asshowninTable11.Underthealternativeurbanscenarios,thatcostwouldincreaseto$8.6billionunderAlternativeUrbanScenario#1andtoover$9billionunderAlternativeUrbanScenario#2.

Table11:TotalFundingRequiredThrough2040toMaintainConditionsat2010Levels(V/Cat1.0)

FacilityType


Improvements





FacilityType


Improvements




UrbanFreeway 262 741 $5,301,455 $3,928,378,000UrbanArterial 1,171 5,329 $4,348,185 $23,171,480,000RuralFreeway 234 520 $3,191,455 $1,659,556,000RuralArterial 2,850 5,851 $2,238,185 $13,095,623,000TOTAL 4,516 12,441 N/A $41,855,037,000


2040E+CNeededCosts

CapacityFundingProjectedCapacityFunding-2017-2020 391,473,000$ProjectedCapacityFunding-2021-2040 2,251,243,000$TOTAL 2,642,716,000$

CostofAdditionalLaneMilesNeededbeyondCommittedProjects $5,210,112,000

TotalCosttoMaintain2010NeededLaneMiles 7,852,828,000$

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