Waymo is coming to Toronto. But the road to get there will be an often snow-covered one — and experts say that will take time and training data to overcome.

The U.S. company said Friday it plans to start testing the streets of Canada's biggest city, with drivers behind the wheel, in the coming days, as part of its "mapping and safety validation work." The goal is for riders to be able to hail one of their driverless cabs by 2028 in the city, Waymo said.

The tests will take place at all hours of the day and night and across all days of the week, in an effort to make sure the technology can adapt to Toronto's "distinct driving conditions." The company didn't expand on what those conditions were. But Steven Waslander, professor and director of the University of Toronto's Robotics Institute, says that likely means snow.

"The big differentiator is really our winter," Waslander said of Toronto compared to other North American cities where Waymo is already up and running.

"The winter challenge is one that [Waymo] haven't demonstrated commercially yet." Waymo first hit the road in warmer cities with little precipitation like Los Angeles and Phoenix, Ariz., and most of the cities it offers ride-hailing services in today are much warmer and dryer than Toronto. That's for good reason, according to Waslander, who says running autonomous cars in the snow comes with all kinds of extra challenges.

Autonomous cars rely on cameras, radar and lidar systems — which map the 3D environment using light — to situate themselves. All of that information is fed into a computer, which makes decisions about where to turn or when to hit the brakes, augmented by lots and lots of training data.

Adverse weather conditions can pose a challenge for all of those systems, says Krzysztof Czarnecki, an engineering professor at the University of Waterloo.

Cameras and other sensors can get covered by snow and ice, making them less effective. Heavy falling rain and snow can also reduce how well the driving system detects objects — as can snow covering cars or street signs.

Czarnecki says as autonomous vehicles are trained on more data, they get better at detecting obscured objects like snow-covered signs. But he says autonomous systems still struggle to make sense of them more than a human would.

Other drivers also change their behaviour when snow flies, Czarnecki says, making autonomous vehicles more likely to get "confused" by their actions or those of pedestrians.

Adjusting to those kinds of elements takes time, as Czarnecki says the vehicles will need to be tested and fine-tuned in those environments.

"The more challenging the weather, the more challenging the engineering." That's why some autonomous cars already on the road in Canada don't run in poor weather.

U.S. startup Gatik, for example, which runs 50 self-driving trucks for Loblaws in the Toronto area, can drive day or night and handle complex driving situations. But it draws the line at heavy rain or snow. Is Waymo winter-ready?

Steve Waslander, a researcher at the University of Toronto who's been studying how autonomous vehicles function in wintery conditions, says those hurdles are big, but not insurmountable. What's needed are engineering solutions, including more data gathered by driving cars in poor weather which the Waymo system can be trained on.

"All of the existing techniques for detection, tracking, prediction, for planning, for control — they can all be applied," Waslander said.

"You just have to know that you're in these conditions and include that training information in the way you build the system." Waymo has been testing its tech in snow-filled regions, like upstate New York and Michigan's Upper Peninsula. The company is also fully operating in Denver, Colo., and is conducting tests in colder, more northern U.S. cities like Minneapolis and Detroit.

According to the Waymo website, the company has logged tens of thousands of hours driving in snowy weather. The data from those blustery trips is used to train its autonomous driver system — the latest iteration of which has more than 100 million miles of autonomous driving experience — to adapt to all kinds of conditions.

"Today, we operate at below-freezing temperatures in the U.S., including with frost and hail, and we’re validating our system to navigate harsher weather conditions," Waymo said in an emailed statement to CBC News.

Still, more winter driving data is needed. Waymo's product lead for weather told The Verge in 2025 that snowy conditions often made up less than five per cent of total driving data, though the company was using AI methods to augment and make progress on winter driving capabilities despite that.

Waslander says with the expansions into so many other snowy markets will help collect that data. When Waymo arrives in a new city, Waslander says it usually deploys a fleet of 50 to 100 vehicles to map a city in all kinds of conditions.

"If they do that across [multiple] different cities, you know, the percentage of weather conditions that are adverse will continue to grow," Waslander said.

Aside from the data, Waymo uses heaters and mini windshield wipers to keep its cameras clear and sensors ice-free. And while cars are out on the road, they act like "mobile weather stations" according to the company, collecting data about whether the weather is foggy, rainy or something else, and sharing that with the rest of the fleet so other cars can use that up-to-date information.

Still, as of August 2025, Waymo told a tech publication that it hadn't "validated the Waymo driver" to operate completely without a driver in snowy conditions.

But Waymo doesn't plan to deploy its ride-hailing service in Toronto until 2028, which Waslander says he expects will give the company enough time to problem-solve winter-related issues.

Waymo to launch first phase of driverless taxi testing in Toronto Waymo’s driverless cars involved in 68% fewer crashes than human drivers, U.S. study finds Czarnecki expects a phased approach might also be possible, where autonomous cars operating while conditions are good but shut down in bad conditions at first, and gradually stay functional in poorer and poorer weather as the system improves.

That's not unlike what the company has done during extreme weather events such as heavy rain in other cities where it's already operating, pulling service when road conditions are particularly bad. "I see this as a process that will take … a number of years," Czarnecki said.