The NASCAR pace car is not permitted to travel faster than 45 miles per hour. The car is capable of accelerating up to 152 miles per hour or more, but it is against the rules to reach this speed.
The pace car's speed is regulated to help promote safety on the racetrack. This is why the car is also known as the safety car.
It is also the pace car's job to lead the competing cars in the race. It does not remain on the track after completing the initial first pace lap. Pace cars originated between 1960 and 1965.