Why do snow plows create piles of snow at the end of driveways in Mississauga?

Why do snow plows create piles of snow at the end of driveways in Mississauga?
Here’s what the city says:

Windrows are an unfortunate and unavoidable outcome of plowing. Snow plows must push snow to the right and must travel in the direction of traffic up one side of the road and then down the other. The size of the windrow left behind will depend on several factors, including:

- the amount of snow received;

- features in the road such as its width, crescent bends or proximity to intersections; and,

- parked cars which require snow plows to weave in and out and may cause snow to be deposited unequally.

To learn more about snow clearing in Mississauga, visit mississauga.ca/snow or contact 311 (905-615-4311 outside city limits).