Assault is still assault... if it had been shooting a gun and missing... depends on exaclty what the local laws are, but it's worth at least bending the ears of the constabularies. They are known to be utterly apathetic (kinda like teachers when they think a parent wants too much because they have so many kids with "real prblems") ... but a flea in the ear is at least one flea.
The main thing is, the next time the guy might not miss (or he may get more creative); if his license plate is on record already... but don't really get your hopes up on them doing something even wtih the license plate, 'cause all the other driver usually has to do is lie.