Additional insurance is not generally required in Canada if you are adequately insured in the U.S. However to be absolutely sure, call your insurance company to confirm. As others have pointed out, you need proof of insurance, so the card is necessary.
If you are traveling in Quebec, and if you have a collision with another vehicle, Quebec drivers carry a form in their glove compartments called a "Friendly Declaration". It's used instead of calling the police, where each driver completes the required info of personal and vehicle identification, plus a drawing of how the accident occurred. Each party signs the form and each party gets a copy of the form.
It's the onlyProvince following this practice...all others get the police, though in some Provinces like Ontario if the damage is less than $100, personal info can be exchanged by the drivers.
Of course if there are injuries, call 911 and get help. You can still try calling the police, explaining you are from the U.S. in the event of a collision.
What part of our Country will you be visiting?
