I just discovered a great new service offered by the California CHP - apparently mainly for the owners of Speedsters and other roadsters.
Without asking, they will check the accuracy of your speedometer, record their findings in a small certificate, and stop you while you're driving to deliver the certificate. For some reason, they also record the posted speed limit if it differs from what your speedo was reading.
After receiving no such service for many years, driving a variety of less conspicuous cars, I was serviced just this morning - at 8:00 o'clock on a Sunday morning - on only the third drive I've ever taken in my new Speedster. Maybe they notice the 'Speedster' on the side of the car and figure the speedo should be checked?
As I soon found out, though, there is a substantial charge for this service. I guess nothing is free anymore.