Pace Lap split field car (the car I own). In NASCAR two pace cars are used on the first two of what is usually three pace laps under normal conditions. The field of 43 competitors is "split" 22 and 21. The pace cars run at pit road speed in order for drivers to note the RPM of their engines to gauge how fast they can enter and exit pit road without receiving a speeding penalty. In recent years NASCAR teams have installed LED lights that surround the tachometers of each race car that will flash either green or red (calibrated to pace car speed and proper engine RPM in whatever gear each driver decides to use entering and exiting for pit service).