What should a driving instructor teach about maintaining proper tire pressure?

1. Tire pressure does not affect driving safety or vehicle handling at all
2. Proper tire pressure improves handling, braking, fuel efficiency, and tire longevity; check monthly and when cold
3. Only check tire pressure during the annual Massachusetts safety inspection
4. Higher pressure than the manufacturer recommends is always safer for highway driving — check tire pressure monthly when cold using the door-jamb specification.