IDOT, VTTI a guiding light for pedestrian safety

Pedestrian fatalities have been increasing over the last decade nationwide. In fact, 75 percent of those fatalities occur after dark, according to the Governors Highway Safety Association.

To help Illinois “drive zero fatalities to reality,” Illinois Center for Transportation and Illinois Department of Transportation team up in the joint project “R27-202: Roadway Lighting’s Effect on Pedestrian Safety at Intersection and Midblock Crosswalks.”

Rajaram Bhagavathula, Virginia Tech Transportation Institute’s senior research associate, leads the effort with Bernard Griffin and Marshall Metcalf, IDOT’s electrical and mechanical unit chief and traffic project implementation engineer, respectively.

“IDOT looks at all crashes and attempts to find out what the trends are, and there was definitely a trend there,” Metcalf said. “So, we knew it was time to try to get some data and try to pin down what kind of lighting needs to be provided.”

To discover the optimum lighting design, the team investigate four and five lighting designs for intersection and midblock crosswalks, respectively, at three light levels.

“My goal is to bring science into this (and) to be able to test how lighting different parts of the intersection or midblock crosswalk actually affects how drivers can see pedestrians at those crosswalks,” Bhagavathula said.

You want to provide optimal visibility without any of the negative effects of either wasting energy or producing glare at the eye level,” he added.

Key to the project is VTTI’s Smart Road, where the research team built a “one-of-a-kind” system that can replicate four different kinds of lighting at an intersection.

To test the effects of lighting, researchers took 24 drivers on the Smart Road to test their ability to identify child-sized mannequins positioned at intersections and midblock crosswalks.

A groundbreaking aspect of the effort is the team’s investigation of pedestrian safety countermeasures such as rectangular rapid flashing beacons and flashing signs in combination with roadway lighting — the effectiveness of which has never been studied.

Also key to the effort is their investigation on the effect of glare from opposing vehicles on a driver’s ability to identify pedestrians at crosswalks.

“We were able to make recommendations for light levels that actually account for that glare from headlamps — not only the level to which you should light an intersection, but also where should you put the light at the intersection,” Bhagavathula said.

Thanks to their efforts, the team is able to provide recommendations — particularly for lighting midblock crosswalks — that can be implemented on roadways.

“(The researchers) gave very specific recommendations as far as how our lighting unit consultants can design the lighting, what light level and what contrast was needed, and they gave us these recommendations in units that lighting engineers use, so it’s reproducible,” Metcalf said.

The next steps?

Create an IDOT specification before developing a future crash modification factor — a calculation for the expected number of crashes. After which, the team hopes to start deploying the design throughout the state.

“We hope that the project will reduce the incidence of vehicle-pedestrian crashes,” Griffin said. “The research team did an exceptional job in that I have a feeling this is going to be of great benefit to assisting us in developing policies for crosswalks for Illinois roadways.”