text: why do most cars have speedometers that go up to at least 150 when you legally can't go that fast on any road?   first, the speedometer predates the speed limit.  second, they tried reducing the numbers on the speedometer and drivers didn't like it. in fact, they paid extra to buy racing gauges.  and third, speedometers are usually spring activated. the more the go to the right the more the spring is strained. over time the sping gets spung and the needle begins to float and stick and give you inacurate readouts. so. if you keep the needle on the left hand side of the dial it should keep functioning longer and designing the dial to do so makes perfect sense.