Answer: Speeding Up
Explanation:
Force is proportional to the acceleration of an object. The greater the force, the more acceleration will be produced.
When the force on the tire is equal to the weight of the car, the car is reaching a stability as a result of increase in motion.
But when the force of the load on the tire is quite large(most likely several times the weight of the car) and is directed forward, then, the car is at high speed.