[OAC_Sparky]

The 400 Series highways were designed for sustained 120kmh driving, because the limit used to be 75MPH until "the gas crunch" of the late 70's when they lowered it to what it is now.

It's not the speed that is the hazard IMO it's the "difference in speed". On a given highway you have an artifically low speed limit for its design. This, under ideal non-rush-hour driving conditions, creates a mix of people that do a speed that seems "comfortable" ie 120kmh, people that are law conscious ie 100kmh, and people that should get the f*** off the highway ie 90kmh (and in a safety-conscious European country, the police would direct them off the highway or ticket them for driving too slow).

It's this combination of varying speeds, poor road manners and poor safety enforcement that causes the issues.