> In fact, most cars lie to you about the speed - reporting a speed slightly faster than reality. It's a cover-your-ass measure for the car manufacturers because it's illegal to sell a car (in the US, at least) where the speedometer is inaccurate in the other direction, that is, reading slower than actual speed.
Haven't seen that in a long time. Everything I've driven in recent years has a speedometer speed that matches roadside speed sign speed within 1 MPH.
If the law set the speed limit as the hard boundary, with hard punishments for driving at 70, everyone else would drive at 65, occasionally getting close to 68-69.
If the reasonable speed for a road is 70, the legal hard limit could be at 75 to be considerate of this effect. But make 75 the actual hard limit with $200 fines for hitting 75, $1000 fines for hitting 80, and jail time for hitting 85. Make it almost certain to be caught if you hit these hard limits.
I guarantee you fewer people would die on the roads if this is the way things worked.
The graph seems a bit too much. It says that GPS 110 means ~125 on the odo. Although from personal experience I'd say it's more around a delta of 5 at those speeds, and 3 for lower speeds.
Haven't seen that in a long time. Everything I've driven in recent years has a speedometer speed that matches roadside speed sign speed within 1 MPH.