Complex sentence: Few go to right-hand-traffic United States and Canada, where a vehicle must be at least 25 years old before the owner can legally forego U.S. roadworthiness compliance while in Canada the car must be at least 15 years old.
Split into simpler sentences: Few go to right-hand-traffic United States and Canada, and because a vehicle must be at least 25 years old before the owner can legally forego U.S. roadworthiness compliance. In Canada the car must be at least 15 years old.