I live in Markham, probably as bad as Brampton for cars, fortunately we don't have as many transports and gravel idiots.
Why are these two areas so bad is a discussion itself, but the fix is simple IMHO -- enforcement and education.
Markham is getting stupid. To stop bad outcomes, the are using a stupid number of controls. They dropped speed limits from 80 to 60@70 on rural arterial roads, added hundreds of street lights on the main roads, changed side street intersections from 2way to 4 way stops, and lately are eliminating right on red at major intersections.
The latest the thing I noticed is they de-synchronized traffic lights on 16th, a major east west road across the city. When it was synchronized, 48 to 404 took about 12 minutes, it's now 25 minutes.