On the contrary, my first car still had an analog speedometer. It really sucked when it failed because the failure mode was that it turned decidedly non-linear

On the contrary, my first car still had an analog speedometer. It really sucked when it failed because the failure mode was that it turned decidedly non-linear past about 50 mph indicated. The first time I drove it after the failure I hadn't driven it in probably a couple months and I was driving it at night without any traffic around. I wound up getting pulled over on the highway and the indicated speed was off by 15 mph. At least with a digital speedometer almost every failure mode is going to be obvious and not some subtle accuracy degradation. Part of the supposed rationale for police almost always not enforcing the speed limit until a good margin over is because of the historic inaccuracies of speedometers. Nowadays assuming someone hasn't modified some gear ratio or fitted the wrong size tires you can more or less be assured that the speedometer will be quite accurate.