A number of Montreal public transit riders say they were alarmed to learn that city buses are exempt from a law requiring all vehicles to have snow tires by Dec. 15.

The Society de transport de Montreal says there simply aren’t proper snow tires available to outfit their fleet of buses. Instead, the STM customizes all-season bus tires to adapt them for the ice and snow.

“We provide our buses with new tires on the front and traction tires on the wheels,” STM spokesperson Philippe Dery told CTV Montreal. “It’s really sort of a homemade recipe, but that works for us.”

Dery added that the city does its best to plow and salt the roads, especially the bus lanes.

The STM says it typically sees around 12 minor collisions after a snowstorm in Montreal, out of approximately 1,400 buses that operate during rush hour.

“Unfortunately, incidents are bound to happen,” Dery said.

With files from CTV Montreal