Make sure you brush all the snow off your car. Iowa State Troopers could give you a ticket for failing to remove all the snow from your car's windows. State troopers admit that tickets for this offense are rare, but will be given out if obstruction of view causes and accident. Each violation for driving with snow on your car's windows is $50. It's not illegal to drive with snow on your car roof, but it can be hazardous to other motorists.
In New Hampshire, under Jessica's Law, it's illegal to drive with snow on your vehicle. A woman named Jessica was killed when snow from a vehicle caused an accident in which she was killed.