They are the latest in crosswalk safety and have been installed across Canada and the U.S. at a cost of thousands of dollars each.
But the pedestrian-countdown signals in this country’s biggest city seem to have actually increased crashes between people and cars, a detailed new study suggests.
After a second analysis of data that they had studied and reported on earlier, researchers at the Hospital for Sick Children concluded that the signals at almost 2,000 Toronto intersections were linked to a 26% increase in the rate of collisions.
The rate of serious or fatal pedestrian-automobile crashes jumped even more — by 50%, they reported in the journal Injury Prevention.
The authors theorize that the descending numerals at intersections — rather than injecting added caution — may be encouraging some drivers and pedestrians to hurry through too late.
“It doesn’t look like a magic bullet thing for injury reduction,” said Dr. Andrew Howard, a University of Toronto surgery professor and medical director of the Sick Kids trauma program. “People may be spending that information on convenience rather than safety. As the signal goes down … they’re more likely to cross, and cross with less time.”
The good news, however, is that the countdown does seem to change people’s behaviour. With tweaks such as having the countdown end earlier, they could have the desired effect, said Dr. Howard.
A spokeswoman for the City of Toronto said traffic experts there could not comment until they had had a chance to thoroughly review the study.
In other cities where the signals have been adopted widely, meanwhile, officials insisted Thursday the initiatives have been a success.
Calgary has installed the countdown signs at 195 intersections and has determined that they are not causing more accidents, said Jennifer Thompson-Goldberg, a spokeswoman for the city’s transportation department. A study is underway to more precisely measure their effect, she said.
“We have found that they are doing their job,” said Ms. Thompson-Goldberg. “They do provide more information for pedestrians on when it is safe for them to cross.”
She said one difference between the two cities that might explain varying results is that Toronto, being much more populous and more densely populated, has far greater numbers of pedestrians on its streets.
One of the few other scientific studies of the signals’ impact was conducted in San Francisco, where a 2006 analysis of nine pilot locations suggested that they had reduced collisions there by more than 50%.
After the city rolled out the devices at 569 intersections, it determined that the number of pedestrian-injury collisions still decreased, but by a more modest 22%, said Frank Markowitz, senior transportation planner with the California municipality.
It is possible Toronto’s signals are timed differently than those in San Francisco, where the countdown ends before the yellow light, he said.
The Toronto researchers looked at pedestrian accident statistics from 2000 to 2009, with the signals implemented in the last three years of that period.
Their original study concluded that the countdowns had no impact, up or down, on the collision numbers.
Then they performed a more sophisticated statistical analysis of the data, factoring in trends in accident rates over time, including an overall drop in pedestrian collisions, as well as the effect different seasons have on the statistics, said Dr. Howard.
It is an “observational” study and not the same as doing a strictly controlled experiment, but the result seems accurate, he said.
“I think what we’re seeing here is our best estimate of what’s really going on at those intersections,” said the orthopedic surgeon and health policy researcher. “I’m fairly certain that what we’re seeing is an increased number.”
He and his colleagues now want to study whether, as suspected, the countdown signals, designed as an aid to pedestrians, are having an effect on the behaviour of drivers as well.
If, in fact, motorists are accelerating toward an intersection because of what the numbers tell them, they will have less time to take corrective action to avoid a pedestrian, and less control over the vehicle, Dr. Howard said.