Research by two former University of Toronto students found that the signals — installed in 2006 at intersections throughout the city and showing how much time is left before a light changes — may be bad for drivers.
Between 2004-08, the researchers collected data about nearly 1,800 intersections in Toronto.
Where there were countdown clocks, the researchers tracked five fewer pedestrian collisions a month. Meanwhile, vehicle collisions went up by 22 a month.
Stepping on the gas
The researchers suggested that some drivers may be stepping on the gas when they see that time is running out.
"Everyone's just in such a rush that you see it all the time," Jobin Vikili, a pedestrian, told CBC News.
The study says the countdown clock can make some drivers speed up, and others slow down causing rear end collisions.
But in some cases the accidents are a result of drivers trying to avoid foot traffic. And, police say, pedestrians often break the rules.
"Unfortunately, when people are looking they think ‘Oh I've got 10 seconds to cross,’ that's not what that means,” Toronto Police Const. Clint Stibbe said.
City officials told CBC News they also not convinced of the study's findings, saying the numbers have stayed stable at about 52,000 crashes a year.
"We're a little perplexed," Mike Brady, Toronto’s Manager of Traffic Safety, said. "Over the past ten years there hasn't been a dramatic increase in the numbers,” he said.