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In the EU, speedometers are not allowed to display a speed that is lower than the speed the vehicle is traveling. Manufacturers calibrate speedometers to comply with this regulation as they would not be allowed to sell their cars if they did not. Reference - EU Regulations for Speedometers (75/443/EEC) The speed indicated must never be less than the true ...


17

Germany is an interesting case to study this, as they have stretches of highway with and without speed limits. In a study done in the state of Brandenburg, the effect of putting a speed limit on stretches of highway has been studied by comparing the accident statistics before and after the new limit. On two stretches the speed limit was changed from no ...


14

I don't think speedometers are deliberately set to read high, but you are less likely to get a speeding ticket that way than if they read too low. If they read high, you can guarantee to be below the speed limit, even when your speedometer indicates you're slightly over. EDIT The first sentence above conflicts with what follows below: if the manufacturer is ...


8

Generally, every car has a specific speed where fuel efficiency (i.e. miles traveled per gallon) is highest. This is mostly around 40 - 60mph (~65 - 95 km/h). Above and below this speed fuel efficiency decreases. So if you travel the same distance, you will use more fuel and therefore produce more pollution. In this paper the authors use a pretty ...


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