1-1 low cost safety improvements. 1-2 introduction highway traffic fatalities trend

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LOW COST SAFETY IMPROVEMENTS

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Introduction

Highway Traffic Fatalities Trend43,220

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10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

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Introduction

• U.S. Highway System– Fatality Rate has decreased or remained

same (as Traffic is Increasing)– But over 42,000 Deaths & 2,920,000 Injuries per

Year

• Lane Departure and Intersection Crashes– Engineering focus areas– Rural crashes (70% of fatals)

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Introduction

Rural Road Safety by The Numbers

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Fatality Rate is 2.5 times that for Urban Roads.

40 % of Travel and 60% of Fatalities

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Introduction

Safety

“Safer”- a relative term

– an absolute

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Is this road ‘safe’ or ‘unsafe’?

LightingAdvance Warning Signs Delineators Chevrons Shoulder Rumble Strip

Which of these low cost measures are required (i.e., nominal requirement)?

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Substantive and Nominal Safety

• Nominal Safety is examined in reference to compliance with standards, warrants, guidelines and sanctioned design procedures

• Substantive Safety is the actual crash frequency and severity for highways or roadways

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Nominal Safety

Nominal Safety – Advance Warning Sign + Advisory Speed Plaque

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Nominal Safety


1st Step

Speed limit = 45 mph Traffic Volume = 2,000 - Expect 2 crashes per year at this traffic volume

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Nominal and Substantive Safety


1st Step 2nd Step

Advance Warning Sign + Advisory Speed + Chevrons = “Safer” = Substantive Safety

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AASHTO Strategic Safety Plan Guidebooks

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Typical Benefit/Cost Ratios

* From MN DOT Traffic Safety Fundamentals Handbook

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The Tools – Roadside

Hazards

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Roadside Hazards

Scope of the Roadside Problem

About one in three of all highway fatalities is the result of a single vehicle run-off-the road Crash

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Roadside Hazards

Drivers May Leave the Roadway As A Result Of:

Driver Error

Collision Avoidance

Roadway Condition

Vehicle Component Failure

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Roadside Hazards

Driver LimitationsPerceive 2 or more events per second Make 1 to 3 decisions per secondTake 30 to 120 actions per minuteCommit at least one error every 2 minutesAre Involved in a hazardous situation every 2

hoursHave 1 or 2 near collisions per monthAverage 1 crash every 6 years

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Roadside Hazards

Trees Utility Poles Light Poles Sign Posts Mail Boxes Steep Ditches Edge Drop Off’s

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Countermeasures for Roadside Hazards:

1. Trees – removal & restriction of species

2. Utility Poles - relocation

3. Sign Supports – breakaway and shielding

4. Mail Boxes – crashworthy

5. Single-Vehicle Run-Off-the-Road - Rumble Strips and Rumble Stripes

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Countermeasures forRoadside Hazards:

6. Slopes and Ditches

7. Rumble Strips

8. Rumble Stripes

9. “Safety Edge”

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Countermeausures for Trees

Proven

CRF = 22% to 71%

*NCHRP 500, Volume 3- Guide for Addressing Collisions with Trees in Hazardous Locations

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Countermeasures for Relocation of Utility Poles

Relocate Utility Pole away from edge of pavement

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Reduction in Utility Pole Crashes for Pole Relocation

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Crashworthy Sign Supports

Small sign Supports – less than 50 Sq Foot

Two 1 ½” Holes in a 4” x 6” wood post

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Countermeasures for Street Light Poles

Light Pole within 1 foot of back of curbNon-Breakaway

steel light pole

8 ft

*NCHRP 500, Volume 6, Strategy 15.1 C1 – Improve Roadside Hardware (Light Poles and Sign Posts)

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Countermeasures for Mailboxes

8” hardened steel gas pipe

*NCHRP 500, Volume 6, Strategy 15.1 B2 – Remove/Relocate Objects in Hazardous Locations

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Update/Replace Roadside Hardware

Replace Antiquated Guardrail and Terminals

NCHRP 500, Volume 6, Strategy 15.1 C1 – Improve Roadside Hardware

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Update/Replace Roadside Hardware

NCHRP 350 compliant end terminal

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Countermeasures for Slopes

Non-recoverable slope

Power pole in toe of ditchDrop- Off

*NCHRP 500, Volume 6, Strategy 15.1 B1 – Design Safer Slopes and Ditches

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Countermeasures for Slopes

Ditch Filled In

Traversable Slope

NCHRP 500, Volume 6, Strategy 15.1 B1 – Design Safer Slopes and Ditches

“After Condition”

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Countermeasures for Run-Off-the-Road Crashes

Rumble strips are intended to supplement pavement markings

Adds sound and vibration to the visual benefits of painted markings

Provide a drowsy, inattentive, or distracted driver with a clear warning that the vehicle has left travel lane…

Provides some reaction time before the vehicle leaves the road

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Countermeasures for Run-Off-the-Road Crashes – Edgeline Rumble

StripsCRF = 20 to 49% for 2 Lane

NCHRP 500, Volume 6, Strategy 15.1 A1 – Install Shoulder Rumble Strips

Tried

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Countermeasures for Run-Off-the-Road Crashes – Centerline

Rumble Strips

Two-Lane Hwy Undivided 4-Lane Hwy

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Rumble Stripes

NCHRP 500, Volume 6, Strategy 15.1 A2 – Install Edge line “Profile marking”

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Rumble Stripes

Mississippi

Rumble Stripes on MS 589

NCHRP 500, Volume 6, Strategy 15.1 A2 – Install Edge line “Profile Marking”

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Rumble Stripes

Michigan initiative with edge line painted over shoulder rumble strip

Normal Edgeline

Rumble Edgeline

Comparison of painted edgeline in RainNCHRP 500, Volume 6, Strategy 15.1 A2 – Install Edge line “Profile Marking”

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Rumble Stripes

Michigan initiative with edge line painted over shoulder rumble strip.

Normal Edgeline

Michigan I-75- After 1st Winter

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Reducing Edge Drop Off Crashes

Example of Edge Drop-Off Crash Normal

Edgeline

County Road recently resurfaced – Edge drop-off resulted in 3 Fatalities

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Reducing Edge Drop-Off Crashes

Normal Edgeline

Edge Drop-off

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Pavement Edge Rutting and Drop-Offs: Edge rutting occurs on all sections of roads Usually a small percentage of road length Caused by errant vehicles in conjunction

with erosion Common in curves and near turning

movements Mailboxes

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Normal Edgeline

“Safety Edge”

NCHRP 500, Volume 6, Strategy 15.1 A8 – Apply Shoulder Treatment

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The Safety Edge

Helps errant vehicles to maintain stability particularly on roadway re-entry

Effective up to 5 inches of pavement depth

Beneficial in reducing Tort Liability during construction & after project completion

NCHRP 500, Volume 6, Strategy 15.1 A8 – Apply Shoulder Treatment

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The Safety Edge

Demonstration Project in Georgia

“Shoe” Installed in Screed

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The Safety Edge

Demonstration Project in Georgia

The “Safety Edge”

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Countermeasures for Roadside Hazards

“Delineate Hazards”

*NCHRP 500, Volume 6, Strategy 15.1 B3 – Delineate Trees or Utility Poles with Markers or Retroreflective Tape

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The Tools – Signing &

Markings & Lighting

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Signing & Markings & Lighting

Signs:• Warning Signs• Unexpected Hazards• Curves• Right of Way Control• Regulatory Signs

Discussion

Markings:• Centerline• Edgeline• Markers• StopBars

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Signing Countermeasures

• Traffic Signs have the 2nd Highest rank in terms of benefit to cost of all safety countermeasures

39% Fatalities15% Injuries

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Warning Signing

Purpose: …to call attention to unexpected conditions and to situations that might not be readily apparent to road users

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Warning Signing for Curves

NCHRP 500 Strategy 15.2 Horizontal Curves

25% of all Highway Fatalities occur on Horizontal Curves

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Case Study: Warning Signs for a Curve

Sweeping Horizontal Curve with alignment “hidden” by vertical crest

Substantive Safety Record

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Case Study: Warning Signs for a Curve

CRF = 22% with Advisory Speed

Tried

CRF = 18%

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Right-of-Way Regulatory Signing

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Install YIELD or STOP Control

CRF = 45%

Tried

2-Way STOP CRF = 35%

*Missouri HAL Manual

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Change 2-Way STOP to All-Way STOP

CRF = 53% for all crashes

*NCHRP 500, Objective 17.1 F2 – Provide All-Way Stop Control at Appropriate Intersections

CRF = 84% for Right Angle Crashes

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Visibility of Right-of-Way Regulatory Signing

(Supplemental Stop Sign in Island)

*NCHRP 500, Strategy 17.1 E3 – Install Splitter Islands on Minor Road Approaches

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Visibility of Right-of-Way Regulatory Signing

(Stop Sign in Island) Three Stop Signs

NCHRP 500, Strategy 17.1 E3 – Install Splitter Islands on Minor Road Approaches

CRF = 11% All Crashes

CRF = 36% Right Angle Crashes

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ObservationTypical layout of intersection guide signs intercepts sight lines from the stop signs.

SuggestionDevelop/adopt a revised typical layout that relocates all of the signs away from the intersection.

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Signing

Existing Typical Layout of Trunk Highway Guide Signs

State Trunk Highway

CountyHighway

Some intersections also contain “Adopt A Highway” signs mixed with intersection guide signs.

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Signing

6’-8’ off edge of edgeline

Revised Typical Layout of Trunk Highway Guide Signs

State Trunk Highway

CountyHighway

Relocate all “Adopt A Highway” signs that are mixed in with the sequence of guide signs on the approach to intersections.

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Markings Countermeasures

2. Markings

A. Centerline and Edge line Warrants

B. Delineation

C. Stop Bar Placements

D. Safety Pylons

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Centerline and Edgeline Markings

Centerline with No-Passing Zones +

Edge lines

(alone)

36%

8%

Tried

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Delineation

Delineation

15% Fatalities 6% Injuries

25% - 58% Run-Off-Road

Tried

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Delineation

Traffic Pylons

Close off Area to Channelize Traffic

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Lighting Countermeasures

Lighting has the highest benefit to cost ratio of any of the traffic safety countermeasures

Proven

CRF = 18% - 70% for spot locations and intersections

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• Lighting of rural intersections reduced crashes by 25 to 50%

- MN study

Proven

NCHRP 500 Strategy 17.1 E2 – Improve Visibility by Providing Lighting

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Illumination of

Rural Curves

Route 376 near Poughkeepsie, NY

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Illumination of

Rural Curves

Cayuga Heights Road just north of Ithaca, NY

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Low Cost Safety Solutions

Examples of Efficient Low Cost Projects:

District 3

County Road & Trunk Hwy intersections

Road Safety Audits

Intersection improvements

District 6

Multi-County horizontal curve project

Install chevrons at horizontal curves

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Low Cost Safety Solutions

SUMMARY

• Data-driven approach

• Lane Departure

• Intersections

• Rural safety problem (70% fatals)

• Random location of crashes

• Proactive Systematic projects

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Thank You….

Dave Kopacz, P.E.

Safety Engineer

FHWA – Minnesota Division

(651) 291-6126

[email protected]

1-1 low cost safety improvements. 1-2 introduction highway traffic fatalities trend

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