In Shattered, speed is an element of gameplay that is measured differently than in the real world. This element is only present in the first Shattered game.
When driving in Shattered, vehicles have a certain top speed that does not go by MPH or KPH. Instead, it is its own measurement. For example, a performance or sports car's average speed is 90-120, and a super car could go up to 130, 130 being the highest possible speed in the game. Some of the slower vehicles like the heavy industrial ones only go speeds up to 45 or 50, which is pretty damn slow.
When the player drives a car, a speedometer will be shown in the bottom left-hand corner which shows 0 at the left end and the vehicle's top speed at the right end. The meter will obviously go up or down accordingly as the player drives.
The measuring speed system does not return in Shattered 2.