Evaluations of Low Cost Safety Improvements Pooled Fund Study

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

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

  
  
  

Picture 1	Looking East on Main	Picture 2	Looking East on Main
Picture 3	Looking East on Main	Picture 4	Looking West on Main

Before Collision Diagram

After Collision Diagram

Results

Picture 1	Picture 2
Picture 3	Picture 4

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

Looking South on US 158	Picture 1	Looking South on US 158	Picture 2
Looking South on US 158	Picture 3	Looking South on US 158	Picture 4

Looking North on US 158	Picture 1	Looking North on US 158	Picture 2
Looking North on US 158	Picture 3	Looking North on US 158	Picture 4

Before Collision Diagram

After Collision Diagram

Results

Picture 1	Picture 2

Picture 1	Picture 2

Before Collision Diagram

After Collision Diagram

Results

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

  
  
  

Picture 1	Picture 2

• Fatal Crash History:

  –	January 1999 through June 2005

• 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

Picture 1	Picture 2
Picture 3	Picture 4

Picture 1	Picture 2
Picture 3	Picture 4

Picture 1	Picture 2
Picture 3	Picture 4

* 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 projects	15
  –	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 2002	102
  	projects will be assigned from the 2003 completions
  –	190 Spot Safety project evaluations are on the web that
  	were completed through December 31, 2006:

• http://www.ncdot.org/doh/preconstruct/traffic/Safety/ses/projects/completed.html

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.

Contact Information

SHAWN A.TROY, PE (919)–2897 stroy@dot.state.nc.us

Traffic Safety Unit Website:http://www.ncdot.org/doh/preconstruct/traffic/TSU/default.html

< Presentation 18 | Index >