Money !! Harriette . Start off with vehicles that are used for a profit ( Like Cart rental , Trucks for delivery , Taxies or even anything with a speedometer Ext ..)Possibly convince the town to raise the permit fee 4x with a option to pay the same fee if they prove the top speed of the vehicle is not above a acceptable limit . A good use of that radar gun. the police department will then have to get involved with the process and be aware of the actual vehicles on the roads . Also a good time to give them a safety evaluation . we all know some of those trucks are not road worthy . That might Be an incentive to install a speed limiter to the Vehicle .