Roadway Safety for Local Agencies Doug Bish Traffic Services Engineer Oregon Department of Transportation

Roadway Safety for Local Agencies

Doug BishTraffic Services Engineer

Oregon Department of Transportation


Diagnosing Crash Problems

The problem is this person has a moose in his car, most problems are not so easily diagnosed!


Diagnosing Crash ProblemsSteps to Diagnosing Safety Problems• Quantify crashes by type and severity• Determine if there is a problem:

– abnormally high crashes in one or more areas; or – just high but normal patterns.

• Determine possible source of problem (major causes).

• Evaluate possible improvements for:– Potential crash reductions– Cost benefit of improvements.


Diagnosing Crash ProblemsDiagnosis of a problem is not always self evident and

requires expert knowledge:• A “high” crash site does not always mean there is something abnormal or that there is

cost effective fix. • No baseline for determining if crashes are “high but normal patterns” or “there is

abnormal patterns”• Don’t always know best “treatment” for high crash location • Hard to identify the best candidate mitigations for improving safety


Step 1 – Review Data (looking for patterns)

•Review and summarize data by:

•Crash type (Rear-end, Sideswipe, Angle, Turning, Head-on, etc)

•Crash severity (Fatal, Injury A, B, or C and PDO)

•Direction of travel

•Contributing circumstances (Lighting condition, road conditions, weather, impairment, etc)


Crash Data

• Can be obtained with a call to ODOT’s Crash Analysis and Reporting Unit

(Robin shared with you some ways to obtain the data – it easier than you think)


Scatter Plots


Yearly Fatal and Injury Rates


Crash Graphing Tool – day of the week, time of day, road condition (wet, dry), light condition (dark, light, dusk), alcohol impairment, crash type


Crash Summary Database

Something like this will be available with the new SPIS


Collision Diagram Tools


Investigating in the Field

• Sometimes all the slicing and dicing of data doesn’t help

• An important part of any investigation is to gather information from different perspectives


Investigating in the Field

• Visit the site, approach the area from all directions– If it is an intersection drive all legs of the

intersection• Take along a peer with different expertise• Talk to staff maintaining the roadway (or meet

them at the site)• Talk to public from around the area

(neighbors or business)• Talk to enforcement and EMS


Choosing a Solution

• Once you have an idea of the problems you can begin to consider different fixes

• Try to avoid choosing solutions until you have gathered all the facts!

• Then compare different solutions by cost and benefit


Crash Reduction Factors

Listed by Improvement Type

Rural Urban Fatal Non-Fatal PDO

ROADSIDE IMPROVEMENTS

Barrier & Guardrail:

Guardrail - install or improve X X 44-47 42-47 -

Guardrail at bridge end - install or improve X X 90 20-45 20-45

Median barrier - concrete, 3-6' shy distance X X 90 10 -10

Median barrier - concrete, 7-12' shy distance X X 85 5 -25

Median barrier - any X 60 -20 -40

Median barrier - metal X X 75 2 -28

Median barrier - cable X X 36 20 41

Install animal fencing X X 70-90 70-90 61

impact attemuators X X 75-90 50 5-50

Clear Zone:

Clear gore area X 50 50 25

Flatten side slopes from 1:2 to 1:4 X 7 7 7

Flatten side slopes from 1:2 to 1:6 X 15 15 15

http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/excel/CRFWorksheet.xls


Benefit/Cost Worksheethttp://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/excel/BC_Form.xls


Low Cost Countermeasures

• Handouts – Low Cost Safety Solutions excel spreadsheet


National Publications• Low Costhttp://docs.mvrpc.org/safety/

Low_Cost_Local_Roadway_Safety_Solutions.pdf

• Lane departurehttp://www.t2.unh.edu/nltapa/Pubs/PLD-1.pdf

• NCHRP Safety Emphasis Guides

http://safety.transportation.org/guides.aspx

• Highway Safety Manual(Available Spring of 2010)


Questions?

Doug Bish

Traffic Services Engineer

Oregon Department of Transportation

http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/highway_safety.shtml

Documents

Roadway Safety for Local Agencies Doug Bish Traffic Services Engineer Oregon Department of Transportation