Here in Canada we do have tests like that. If you are over some age, 80 I think, you have to come for a physical that will determine if you can drive or not. Also if your physician sees that you are suffering from something that might make you a bad driver, or unsafe, he is obligated by law to report you to the trasnportation office for immediate licence suspension and it will remain suspended until your doc says that you are now fine to drive.
And here in Toronto, I would say that I get scared a lot more when some hot head in a suped up civic pulls up behind me then an elderly driver who knows his or her licence might be taken away in the blink of an eye.
Then again I just failed my road test for being too careful in a school zone, I guess that makes me a bad driver as well
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