A curb extension, also called a bulb-out, at the corner of St. Clair Ave. West and Wychwood Ave. in Toronto. Curb extensions shorten the distance pedestrians have to cross.Supplied
What’s the point of those bump-outs at crosswalks? There are a bunch in my subdivision, and I find them frustrating as a driver because I have to slow down at every single one – even if nobody is waiting to cross. Shouldn’t they only be putting them where somebody has been seriously hurt or killed in a crash? – Peter, Ontario
Curb extensions at crosswalks are there to calm traffic – and pedestrians’ nerves.
“The primary goal would be the reduction of crashes, which comes about from the reduction in speed,” said Craig Lyon, director of road safety engineering with the Traffic Injury Research Foundation (TIRF), an Ottawa-based not-for-profit. “But that reduction in speed also makes it a more comfortable place to be for vulnerable road users. If you’re going to send your kids out on bicycles, [you want] lower speeds.”
Curb extensions, also called bulb-outs or bump-outs, extend the sidewalk into the parking lane.
They’re meant to shorten the distance that pedestrians have to cross, make it easier for drivers to see a pedestrian waiting to cross (and for pedestrians to see cars) and physically make drivers slow down when approaching them because the roadway narrows.
Because they make a corner wider, drivers also have to slow down when turning around it to avoid hitting the curb.
“You reduce the speed, especially around where people are going to be crossing,” Lyon said. “And you give extra space for a bunch of people waiting to cross.”
On average, more than 300 pedestrians are killed every year on Canadian roads. About 30 per cent of all fatal crashes and 40 per cent of all serious injury crashes between pedestrians and cars happen at intersections, according to Transport Canada.
Curb extensions are usually part of a plan – which can also include speed bumps, lower speed limits and photo radar – to get drivers to slow down over all, especially on residential streets.
“Curb extensions … provide visual friction which can result in more cautious driving and can result in slower vehicle speeds,” states a City of Toronto road engineering guideline. “Reducing excessive speeds provides additional reaction time and reduces the impact speed in the event of a collision.”
While permanent curb extensions require construction, Calgary has used temporary, pre-made curb extensions, which can be dropped off anywhere.
Taming the need for speed?
Curb extensions narrow the roadway and force drivers to slow down.Supplied
So, do curb extensions prevent crashes between cars and pedestrians?
“[They] have been found to reduce vehicle speeds, collision rates and crash severity,” Stephanie Cowle, a spokeswoman for Parachute, a Toronto-based not-for-profit focusing on injury prevention, said in an e-mail.
For example, a 2012 study of 1,871 Montreal intersections found 25 per cent fewer collisions between cars and pedestrians when there was a curb extension. A follow-up study of Montreal intersections in 2020 found that curb extensions reduced pedestrian injuries.
A lot of the safety research focuses on the benefits of lower speeds over all, TIRF’s Lyon said.
So, it can be tough to measure how well curb extensions work at every single intersection where they’ve been installed, he said.
“We could look at the effects on speed, the effects on crashes or conflicts between vehicles and pedestrians – but it’s hard to get that data,” Lyon said.
But Lyon rejects the idea that traffic-calming measures such as curb extensions, speed bumps and roundabouts should only be installed at locations where there have already been serious crashes.
Instead, cities need to work at lowering speeds and preventing crashes over all, he said.
“Crashes are random in nature – especially if you’re only looking at fatals,” Lyon said. “The goal should be pro-actively identifying situations that we know are inherently not safe and addressing them in a low-cost measure. You have to do things at low cost because you can’t go and redesign every metre of roadway or every single intersection.”
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