Lower speed limits protect pedestrians in your neighbourhood.Andrey Armyagov/iStockPhoto / Getty Images
Does setting speed limits to 40 kilometres an hour or less on residential streets actually make them safer? Going that speed on my way to work feels awfully slow. Is it actually doing anything? – Greg, Edmonton
Lower speed limits make roads safer for the people in your neighbourhood – especially if they’re not in a car, safety experts say.
“[By] slowing speeds you’re going to be reducing crashes in cities – it’s just a given,” said Craig Lyon, director of road safety engineering with the Traffic Injury Research Foundation (TIRF), an Ottawa-based nonprofit. “There’s evidence from around the world that it’s effective.”
While provinces generally set speed limits on residential streets at 50 kilometres an hour, except for school and playground zones, many cities across Canada have been lowering that to 40 or 30 kilometres an hour.
Of the 10 biggest Canadian cities by population, only Winnipeg hasn’t permanently implemented speed limits of 40 kilometres an hour or lower on at least some residential streets – although it started a pilot program in 2023, according to Parachute, a Toronto-based nonprofit focusing on injury prevention.
Since 2021, Toronto has been lowering speed limits to 30 from 40 kilometres an hour on local roads.
The point is to slow drivers to reduce both the number and severity of collisions, said Karim El-Basyouny, a professor of transportation engineering at the University of Alberta in Edmonton.
“[Lower speeds] typically result in shorter stopping distances, giving drivers more time to react to unexpected situations,” El-Basyouny said in an e-mail.
A 2019 analysis of collision research found that a pedestrian has a 50-per-cent chance of dying when hit by a car travelling at 59 kilometres an hour. That drops to 29 per cent at 50 kilometres and hour, 10 per cent at 37 kilometres an hour and to 5 per cent at 30 kilometres an hour.
Even just a one kilometre an hour hike in speed can make it more likely that a pedestrian will die in a crash, the analysis showed.
The need for speed?
The lower limits are working, El-Basyouny said.
A 2024 study of Edmonton, which El-Basyouny co-authored, showed a 25-per-cent drop in collisions between pedestrians and cars and a 31-per-cent drop in pedestrian injuries and fatalities after speed limits on residential streets were lowered to 40 kilometres an hour from 50 there in 2021.
In Toronto, a 2020 study showed an even greater drop in collisions and pedestrian injuries and fatalities – 28 per cent and 67 per cent, respectively – when speed limits were lowered to 30 kilometres an hour from 40.
So, does that mean 30 kilometres an hour is better than 40 everywhere?
“There isn’t a universal consensus on the best speed limit for residential areas,” El-Basyouny said. “Different jurisdictions and studies have shown varying results.”
Instead of setting a one-size-fits-all limit, cities also need to look at the road design and traffic flow, he said.
If speed limits are set too low for the design of the road, drivers may just go faster, said TIRF’s Lyon.
“It has to be done in a smart way,” Lyon said, pointing to 30 kilometre an hour limits in his Ottawa neighbourhood. “On my street and most streets, [30] makes perfect sense, but then there’s a collector street where it just doesn’t work – even if you’re going 40, it feels like you’re going 20.”
Studies show that if lower speed limits aren’t enforced, more drivers just ignore them, Stephanie Cowle, a Parachute spokeswoman, said in an e-mail.
Plus, cities may need to install traffic-calming measures, including speed bumps, roundabouts and bump-outs at crosswalks, to physically force cars to slow down.
“When these roadways were designed originally, they were designed at higher speeds,” Lyon said. “You can’t totally reconstruct entire roads everywhere across the city – that would costs trillions of dollars. So, instead, what do we do that’s going to be relatively low cost and effective?”
But if everyone’s going slower, won’t it cause congestion?
“We do not expect a significant impact, as these roads are typically not designed to carry large volumes of traffic at higher speeds,” El-Basyouny said.
Also, lower speed limits in your neighbourhood shouldn’t significantly slow down your trip to work, Cowle said.
“The real difference in your commute might be a minute or so,” she said. “Slower speeds also reduce congestion because more vehicles are travelling at a constant speed, and that improves traffic flow.”
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