I just said it's possible, although I know that at least in a vehicle on vehicle accident a police report is completed at the scene of the accident. Among other things, the police ask the driver(s) how fast they were going, but obviously have no way to verify the answers unless there were witnesses. Given that the police still haven't laid any charges against the driver at this point, it seems pretty clear that none will be forthcoming. Presumably the driver didn't actually break the law, but we'll probably never know what exactly happened.
It would cost a fortune to install physical restrictions given how many streets there are like this one throughout the city - designed for speeds that are unsafe for pedestrians. Also, those main roads you speak of can't handle more (or faster) traffic anyway - Eglinton is residential through Leaside and the other two are predominantly "main street retail" which should have similar speed limits to residential streets given the amount of foot traffic. Forcing traffic onto other streets only shifts the problem, it does not solve it.