In some jurisdictions the law says that the car speedometer must show a higher speed than the correct one (as long as tyres aren't above the correct pressure),

In some jurisdictions the law says that the car speedometer must show a higher speed than the correct one (as long as tyres aren't above the correct pressure), so that the driver can "trust" the speedometer to avoid them a speeding ticket. On my car 140 km/h on the speedometer corresponds to 128-130 km/h on the GPS.