What's more important to you? Are there a lot of other people around where you live (mainly younger kids)? Basically, could he be putting anyone else in danger?
What your mother can do is ask for a "patrol by" due to speeders in the area. This basically tells officers that there are speeders out in your area and you wish for officers to patrol the area for the residents safety. Your mother won't be pointing the finger in any direction. If he happens to be around and sees an officer but isn't "getting on it", he'll remember that next time he passes through and he'll keep it under control..........or he could get on it like normal and eventually lose it because maybe he's young and can't handle it. Maybe he runs off the roadway losing control wrecking the Camaro, wrecking into your house or your neighbors, maybe hurting someone....or even you.
Or, maybe you run into him one day and if you don't like what he's doing, tell him to knock it off. I tell you...there's places to get on it and there's places to get on it if you know what I mean.