US 421 Centerline Rumble Strips in Chatham Co.

Renee B. Roach, P.E. and Al Grandy

May 2, 2007

Regional Traffic

One of the Regional Traffic office’s main task is to reduce the number and severity of

crashes and decrease the crash potential on all NC roadways. We complete this mission

by identifying, developing, implementing and evaluating safety and traffic operational

projects.

LocationUS 421 from approximately SR 2119 to

SR 1010 in Chatham County. This segment of roadway was an active TIP project R-2610 in Division 8

MAP

Problem

The Sandhills Regional Office identified a troubling pattern of cross centerline crashes occurring along this section of US 421. An Engineering investigation was conducted

concerning this pattern and was presented to Division 8 Staff along with a concept of trying an installation of centerline rumble

strips.

Crashes for a 5 yr period

Chatham County US 421 2-lane sectionRecent 5 year crash history from: 01/01/1999 to 11/30/2004

K A B C PDO Total Tr-TrailerAll Crashes 7 7 23 76 202 315 35 122 Dawn Dusk Fatigue

Left of center 5 3 6 15 50 79 17 33 5 2 12Run off road Rt 0 1 5 15 43 64 4 25 1 2 6

Note: The other 2 fatals were a rear-end and a pedestrian.

Out of a total of 315 crashes in a 5 year time frame for a 11.5 mile segment 143 vehicles left their lane of travel

Dark

FatalsLeft of Center Fatal Crashes on US 421 Chatham County from 1999-2005

Driver at FaultDate Time Vehicle Type of Accident Speed Direction Age Local/Out of State # Killed Comments

1 10/10/99 8:15 PM Car/Tractor Trailer Crossed center line 55 mph NB 21 from Cameron, NC 1 Alcohol

2 5/18/01 3:40 PM Car/Tractor Trailer Crossed center line 55 mph SB 70 from Fletcher, NC 1

3 10/5/01 8:45 PM Car/Tractor Trailer Crossed center line 60 mph SB 49 from Greensboro 1

4 11/23/01 8:30 PM Single Car Ran off Road Right 70 mph NB 19 Fort Bragg 2 Driver Charged with DWI

5 5/16/03 8:45 AM Car/Tractor Trailer Crossed center line 55 mph NB 52 Pennsylvania 1

6 8/24/04 1:43 AM Car/Tractor Trailer Crossed center line 70 mph NB 46 Siler City 2 Driver Charged with DWI

7 10/30/04 3:15 AM Car /Car Crossed center line 55 mph SB 19 Sanford 3

8 2/22/05 6:30 AM Car/Tractor Trailer Crossed center line 55 mph NB 24 Siler City 1

9 3/16/05 11:35 AM Car/Tractor Trailer Crossed center line 50 mph NB 46 from Greensboro 1

10 5/3/05 12:39 AM Car/Tractor Trailer Crossed center line 55 mph NB 31 Washington 1 Vehicle unable to stopfor slowed traffic

11 5/26/05 10:35 AM Car/Tractor Trailer Crossed center line unk NB 73 Sanford 1

Solution

• A multi Unit Team of Division 8 staff, Sandhills RTE office, Traffic Safety Systems, and Work Zone Traffic Control was formed

• Team was charged with developing and rapidly implementing an effective corrective countermeasure

• Team worked as an cohesive group to study and discuss site conditions and incident circumstances and save lives on US 421

• SOULTION - INSTALL MILLED CENTERLINE

RUMBLE STRIPS

SolutionCenter Line Rumble Strips

Project Information

• Widen project R-2610A&B started on December 4, 2004

• 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 $ 34,388.00

Results

Significant improvement in reduction of drift across center lane departure type crashes

during critical construction phases

Before and After Before Period (3 Yrs) After Period (1.25 Yr)

7/ 1/ 2002 - 6/ 30/ 2005 8/ 1/ 2005 - 10/ 31/ 2006Percent

Total Crashes Crashes/ Yr Total Crashes Crashes/ Yr Change193 64.3 43 34.4 -46.5

Lane Departure Crashes* Crashes/ Yr Lane Departure Crashes* Crashes/ Yr102 34.0 11 8.8 -74.1

Correctable Crashes** Crashes/ Yr Correctable Crashes** Crashes/ Yr31 10.3 2 1.6 -84.5

Correctable Crashes Crashes Per Year Crashes Per Year PercentCrash Severity Before After Change

Fatal 2.0 0.0 -100.0Class A Injury 1.0 0.0 -100.0Class B Injury 0.7 0.8 20.0Class C Injury 1.0 0.0 -100.0

PDO 5.7 0.8 -85.9

* Lane Departure Crashes include 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.

Benefits • DECREASES FATALS, INJURIES AND CRASHES• Low cost counter measures, B/C = 196 for 11 fatals• Quick Installation• Side Benefit a decrease of speed - people were more

hesitant to pass along this segment • Gathering of empirical data to show this type of

treatment can produce significant decreases in cross centerline crashes

• This data can be shared within and outside of the State• This problem solving (Team Effort) approach can be

utilized for tackling other safety, design, constructability, and maintenance challenges.

Contact

Sandhills Regional Traffic Office

Al Grandy

Renee B. Roach, P.E.

910-437-2614