This is a very good idea that needs some work. Speeding is responsible for thousands of deaths every year, and current enforcement mechanisms are ineffective, expensive, and often unfair. Issues of "individual choice" and "invasiveness" are not relevant, because the decision to speed directly endangers the lives of other people. Physically limiting speed, however, seems ill-advised. As other comments have pointed out, it is sometimes necessary to speed away from a dangerous situation. Another problem is that people with strong feet (pronounced "adolescent males") will be able to speed more than people without--the pedal does not become impossible to depress beyond the legal limit, just harder. Warning lights or noises are far more advisable. These could be combined with systems that record speed limit violations, and report them to authorities if they exceed a certain frequency or severity. These issues will be ironed out with experience. For now, I wish the Canadian regulators good luck.