Well someone going that speed on the 401 really should not be on it and should have taken another road. I would just drive by what can you. You could call *OPP but i would only call that for very dangerous situations. Sometimes i will just flash my lights but they get mad.
There has been a few times where people are driving with all lights off and they get mad at me for trying to help them......
I would just stick to my own business and not inconvenience anyone.
Your best bet would be *OPP if it was really bad (old man going 50 on highway etc)
The cop would probably come and tell them they should not use this road if they dont feel safe at the speed limit as they are making it a hazard and dangerous for others.
I wonder what bear has to say on this. On a second though this person could be under the influence of alcohol and drugs and can not drive properly and is a danger.
Although i rarely will ever dial *OPP. The last time i did there was a sleepy trucker who kept wondering all over the place and changing speeds, and the time before that there was some guy in a car who was actually trying to intimidate, kill, or threaten other cars which obviously are both potentially hazardous situations.
Although if this was late at night and he was in the right lane by himself i wouldn't do anything.
Although if this was a busy time and he was doing this in a passing lane he would be causing a big disturbance and i would call right away before an accident happens.