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Safety Research > Evaluations of Low Cost Safety Improvements Pooled Fund Study > Evaluations of Low Cost Safety Improvements Pooled Fund Study (ELCSI-PFS) Annual TAC Meeting , 2007 >North Carolina DOT
PPT version for Printing

Low Cost Evaluations

Shawn A. Troy, PE
North Carolina DOT - Traffic Engineering Branch

Low Cost Pooled Fund TAC Meeting
June 20, 2007

Low Cost EvaluationsLow Cost Evaluations
Low Cost EvaluationsLow Cost Evaluations
Low Cost EvaluationsTraffic Safety SystemView alternative text
Low Cost EvaluationsLow Cost Evaluations
Low Cost EvaluationsLow Cost Evaluations
Low Cost EvaluationsLow Cost Evaluations
Low Cost EvaluationsLow Cost Evaluations

Directional Crossover - 1

  • Problem Statement:
    –High volume of traffic on mainline
    –Vehicles attempt left turns from the side road
    –Resulting in high number of crashes at the location
    –Signal not considered due to signals on either side of intersection within 600’
  • Countermeasure:
    –Installation of a Directional Crossover
    –Cost: $55,000
    –Project completion - June 30, 2000
    –5 Years and 7 Months - Before and After Data
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Picture 1Looking East on MainPicture 2Looking East on Main
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Picture 3Looking East on MainPicture 4Looking West on Main
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Before Collision Diagram
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After Collision Diagram
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Results

Treatment Information
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Total crashes457055.6
Total Severity Index3.14.542.3
Frontal Impact Crashes334330.3
Frontal Severity Index3.45.562.5
Volume134001700026.9
 
 
Treatment Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal01N/A
Class A00N/A
Class B54-20.0
Class C819137.5
Property Damage Only324643.8
 
 
Frontal Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal01N/A
Class A00N/A
Class B53-40.0
Class C613116.7
Property Damage Only222618.2
 
 
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Directional Crossover - 2

  • Problem Statement:
    –Congestion and high volume of traffic at the intersection
    –Vehicles attempt left turns from the side road
    –Resulting in high number of crashes at the location
  • Countermeasure:
    –Installation of a Directional Crossover
    –Cost: $30,000
    –Project completion - April 9, 1999
    –6 Years and 10 Months - Before and After Data
 
 
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Looking South on US 158Picture 1Looking South on US 158Picture 2
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Looking South on US 158Picture 3Looking South on US 158Picture 4
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Looking North on US 158Picture 1Looking North on US 158Picture 2
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Before Collision Diagram 
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After Collision Diagram 
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Results

Treatment Information
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Total crashes3726-29.7
Total Severity Index12.23.8-68.5
Frontal Impact Crashes334-87.9
Frontal Severity Index11.36.6-41.8
Volume220002940033.6
 
 
Treatment Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal10-100.0
Class A30-100.0
Class B52-60.0
Class C108-20.0
Property Damage Only1816-11.1
 
 
Frontal Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal10-100.0
Class A20-100.0
Class B50-100.0
Class C103-70.0
Property Damage Only151-93.3
 
 
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Before Collision Diagram
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After Collision Diagram
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Results

Frontis St Influence Information
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Total crashes529-29.7
Total Severity Index4.03.0-23.2
Frontal Impact Crashes322633.3
Frontal Severity Index1.03.0201.0
Volume208502765032.6
 
 
Influence Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal00N/A
Class A00N/A
Class B02N/A
Class C26200.0
Property Damage Only321600.0
 
 
Influence Injury Crashes
 BeforeAfterPercent Reduction (-)
Percent Increase (+)
Fatal00N/A
Class A00N/A
Class B02N/A
Class C04N/A
Property Damage Only316433.3
 
 
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Centerline Rumble Strips

  • Problem Statement:
    –11.5 mile segment of rural 2-lane roadway
    –Section bordered on North and South by 4-lane divided roadway segments
    –North is a 65 mph full control access segment
    –South is a 55 mph partial control access segment
    –Construction began in December 4, 2004 to convert 2-lane segment to 4-lane divided roadway to match North and South segments
    –During first 6 months of construction - 4 Fatal Head-On Crashes occurred
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  • Fatal Crash History:
    –January 1999 through June 2005
Left of Center Fatal Crashes on US 421 Chatham County from 1999-2005
DateTimeVehicleType of AccidentSpeedDriver DirectionAgeDriver's Local/Out of State# KilledComments
110/10/998:15 PMCar/Tractor TrailerCrossed center line55 mphNB21from Cameron, NC1Alcohol
25/18/013:40 PMCar/Tractor TrailerCrossed center line55 mphSB70from Fletcher, NC1 
310/5/018:45 PMCar/Tractor TrailerCrossed center line60 mphSB49from Greensboro1 
411/23/018:30 PMSingle CarCrossed center line70 mphNB19Fort Bragg2Driver Charged with DWI
55/16/038:45 AMCar/Tractor TrailerCrossed center line55 mphNB52Pennsylvania1 
68/24/041:43 AMCar/Tractor TrailerCrossed center line70 mphNB46Siler City2Driver Charged with DWI
710/30/043:15 AMCar /CarCrossed center line55 mphSB19Sanford3 
82/22/056:30 AMCar/Tractor TrailerCrossed center line55 mphNB24Siler City1 
93/16/05#######Car/Tractor TrailerCrossed center line50 mphNB46from Greensboro1 
105/3/05#######Car/Tractor TrailerCrossed center line55 mphNB31Washington1Vehicle unable to stop for slowed traffic
115/26/05#######Car/Tractor TrailerCrossed center lineunkNB73Sanford1 
  • Countermeasure:
    – Installation of Centerline Rumble Strips for the remainder of the construction project
    – Centerline rumble strips were installed in 5 days between July 19-28, 2005
    – Total cost for the installation of milled rumble strips, traffic control and motorcyclist signing was $ 34,388
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Before period(3 Yrs)
7/1/2002 - 6/30/2005		After period(1.5 Yr)
8/1/2005 - 1/31/2007		 
Total CrashesCrashes/ YrTotal CrashesCrashes/ Yr Percent Change
19364.35838.7-39.9
Lane Departure Crashes*Crashes/ YrLane Departure Crashes*Crashes/ Yr 
10234.01510.0-70.6
Correctable Crashes**Crashes/ YrCorrectable Crashes**Crashes/ Yr 
3110.332.0-80.6
Correctable Crashes
Crash Severity		Crashes Per Year
Before		Crashes Per Year
After		Percent Change 
Fatal2.00.7-66.7  
Class A Injury1.00.0-100.0  
Class B Injury0.70.70.0 
Class C Injury1.00.0-100.0 
PDO5.70.7-88.2 

* Lane Departure Crashesinclude the following crash types
Ran Off Road - Right, Ran Off Road - Left, Ran Off Road - Straight, Overturn/Rollover, Other Non-Collision,
Fixed Object, Parked Motor Vehicle, Head On, Sideswipe - Same Direction, and Sideswipe - Opposite Direction.

** Correctable crashes involve at least one vehicle crossing the centerline.
Note that avoidance, weather, and passing related crashes were not included.
Avoidance Crashes consist of the following: Other vehicles, movable objects, deer, pedestrians,
mechanical problems, flat tires, blown tires, and medical problems.
Also, only crashes where the first vehicle maneuver involves veering left are included.

Safety Evaluations

  • Safety Evaluation Group
    -2004 15 projects15
    -2005 95 projects (10 to be complete)105
    -2006 102 projects (5 to be complete)107
    -2007 41 projects (145 to be complete)186
    -Above are projects completed through 2002102
    projects will be assigned from the 2003 completions
    -190 Spot Safety project evaluations are on the web that
    were completed through December 31, 2006:


 





AASHTO TIG-CMB

  • Key Topic Areas
    – Contact Information
    – Background and Problem Identification
    – Roadway Design Issues
    - Maintenance Issues
    – Benefits and Evaluation
    – System Threats
    – Barrier Design
AASHTO TECHNOLOGY
IMPLEMENTATION GROUP(TIG)
CABLE MEDIAN BARRIER(CMB)
WEBSITE LAUNCH
Please visit http://tig.transportation.org then click on CMB to find answer to your state’s key question about Cable Median Barriar.
AASHTO TIG-CMBAASHTO TIG-CMB

Contact Information

SHAWN A.TROY, PE
(919)-2897
stroy@dot.state.nc.us
Contact Information
Traffic Safety Unit Website:http://www.ncdot.org/doh/preconstruct/traffic/TSU/default.html

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