If you are buying a new car in Canada, please ask dealer to provide the compliance letter for USA, before you make any payment for the car. If the car is made in Canada USA or Mexico, there will be no duty. If it is made in any other country it will be 2.5% of the price that CBP has for reference. Mine was a 4 year old car, so they did not charge anything. Going to the border should be ok, no need for RI.