NATIONAL MOTORISTS ASSOCIATION

Empowering Drivers Since 1982 Telephone: 608-849-6000

Fax: 888-787-0381 402 West 2nd Street E-mail: nma@motorists.org Waunakee, Wisconsin 53597-1342 Website: www.motorists.org

January 4, 2013

Engineering Certification

UNLAWFUL RED LIGHT CAMERA SYSTEM IN VIRGINIA BEACH

This is to certify that the red light camera system on the northbound approach of Kempsville Road to

Indian River Road in the City of Virginia Beach has been operating illegally ever since it was activated on

March 13, 2009.

Virginia’s red light camera law [Code § 15.2-968.1] explicitly requires that the yellow change interval on

camera-enforced traffic signals be established based on "the recommended methodology of the

Institute of Transportation Engineers." Since 1985, the Institute has been recommending that the

yellow change interval (Y) for through movements be calculated as follows:

Y = t + 1.47V/(2a)

Where:

t = mean value of perception-reaction time (s); set at 1.0 seconds

a = deceleration rate (ft/s2); set at 10 ft/s2

V = 85th percentile speed of free-flowing vehicles determined under good conditions (mph).

On March 17, 2009, pursuant to a FOIA request, the City of Virginia Beach provided a speed study

showing that the 85th percentile speed of northbound traffic on Kempsville Road approaching Indian

River Road is 52 mph. Therefore, the value for the speed variable (V) that must be used is 52 mph.

Hence:

Y = 1.0 + 1.47x52/(2x10) = 4.8 seconds

Accordingly, the current yellow change interval of 4.3 seconds is not in compliance with state law.

I estimate that increasing the yellow change interval to the duration calculated using the ITE

methodology would reduce through-movement red-light-running violations by more than 50 percent.

The City was notified about this on March 18, 2009, and numerous times thereafter. It now appears

that 19 of the 20 camera-enforced approaches in the City have illegally short yellow change intervals.

J. J. Bahen, Jr., P.E.

Life Member: National Motorists Association

Member: Institute of Transportation Engineers

412 Parview Place

Glen Allen, VA 23059

(804) 741-0462

JoeBahenPE@gmail.com 1/4/2013