MD here in the US has a law against nitrous in street cars also. The only way it is allowed on the street is if you put some big ass signs on your fenders and rear bumper on your car to indicate that it has nitrous (the kind of diamond shaped signs that 18 wheelers have on them to indicate flammable gas/hrmful chemicals, etc). And that is only so that you can transport the car with the nitrous in it. It is still illegal to use it on the street. Only reason they even have the law to let you transport it is to allow people to get to and from the track.
