T-bones and other side collisions caused by drivers running red lights have been a problem at several downtown Raleigh intersections, and previous efforts by the city to reduce these kinds of crashes haven’t always worked.
So the city brought back the use of the double red traffic lights, known by traffic engineers as “T” heads because of their shape, at the end of 2012. There are four of them now – at the intersections of Wilmington and Morgan, Wilmington and Edenton, Person and Edenton, and Morgan and Boylan streets. The most recent was installed Jan. 12.
“The idea is the double-head indication brings more attention to the red-light phase,” said Jed Niffenegger, the city’s transportation operations director. “It’s just a visual way of getting across that the light is red.”
So far, these traffic lights have proven “somewhat effective” in reducing T-bone collisions, Niffenegger said.
At the intersection of Person and Edenton streets, where one of the fixtures was first installed, crashes have decreased from 20 between 2010 and 2013, when the light was installed, to nine collisions between 2013 and 2016. But the number of crashes recorded at the intersection of Wilmington and Edenton streets didn’t decline after the new lights were installed.
Niffenegger said additional businesses or apartments and higher traffic can impact the data.
“With an increase in volume, the comparison is not a static, apples-to-apples one,” he said.
“T” heads are one of several “low-cost” tools the city’s safety program uses to reduce collisions caused by red light runs. Other alternatives include warning signs, backplates to improve visibility and lengthening the time between when one light turns red and the other turns green.
The city uses crash data from the N.C. Department of Transportation’s Traffic Engineering Accident Analysis System to determine which intersections are the most hazardous and the highest priority. Staff uses that information to try to figure out what is causing the accidents and if it can be fixed, Niffenegger said.
“If people are running the light running eastbound and it occurs from 6 to 9 (a.m.) it could be sunlight and vice versa when the sun is setting,” he said.
Raleigh will test different methods, but if none prove successful, the city may turn to a more costly alternative – a red-light camera. While “T” heads cost a couple thousand dollars each, Niffenegger said, red-light cameras are expensive throughout the course of their life because of maintenance costs and paying staff to process violations and payments.
But “T” heads and red-light cameras will never stop every collision, Niffenegger said.
“It’s a human compliance issue,” he said. “I mean, whether people are on their phones, whether there are extenuating circumstances, it’s kind of hard for us as engineers to fix a compliance issue.”
Kathryn Trogdon: 919-829-4845: @KTrogdon