An update is coming to Virginia State Police car lights. As the next fleet of Virginia State Police vehicles is being rolled out, the vehicles are being equipped with a new lighting pattern that includes both red and blue lights. The light bars were previously only blue.

The change is based on testing and evaluation by Virginia State Police Driver Training Center staff, nationwide best practices for police vehicle emergency lighting, vendor input, and recommendations from recently published research.

The Science Behind the Color

A team of researchers from the Division of Technology Implementation Infrastructure-Based Safety Systems at Virginia Tech Transportation Institute (VTTI) studied ways drivers can respond faster when they see police cars, as well as ways to make police cars more visible on roadways.

Funded by the National Institute of Justice, the team of VTTI researchers first partnered with Virginia State Police to analyze police vehicle lighting and the responses of drivers in 2014. The most recent study was the first naturalistic traffic assessment of lane-change and speed behavior in proximity to an actively lit law enforcement vehicle conducted on this scale. 

After the state's Move Over Law took effect, the researchers used cameras and radars to determine when drivers changed lanes, and whether their speed changed during an incident or traffic stop. Despite the Move Over Law, 40 officers were killed in 2022 across the nation in traffic-related incidents, a 29 percent increase from 2021, according to the National Law Enforcement Officers Memorial Fund.

The research investigated a variety of conventional and popular alternatives to lighting police vehicles by placing a police vehicle behind a civilian vehicle on the shoulder of a road. The team analyzed a marked police vehicle with four different lighting patterns and an unmarked vehicle with two different lighting patterns in five locations across Virginia, spanning from urban to rural environments and at different times of day.

Researchers found that the use of red lights had a positive impact on traffic behavior. Behavioral impacts included merging to a farther lane earlier and slowing down while passing.