What Causes a Car to Roll on Flat Ground?

[MacGrant]

The main reason for a car rolling on flat ground is releasing the brake too early before the clutch is fully engaged, resulting in insufficient power when the brake is released. The specific causes and solutions are as follows: Specific Causes: First, for automatic transmission vehicles, if the car is parked in N (Neutral) gear on flat ground, it may roll, especially when parked on a slope. The N gear is equivalent to the neutral position in manual transmission vehicles. For temporary parking, always remember to engage the parking brake; otherwise, the car may roll. After parking, shift to P (Park) gear and then engage the parking brake to prevent rolling. Solutions to Prevent Rolling: When starting the car, the general procedure is to press the brake with the right foot. After pressing the brake, slowly lift the clutch with the left foot. If the torque transmitted from the engine to the tires gradually increases, and the clutch is fully released, the car will not roll. Then, after reaching the semi-engagement point, the engine begins to deliver torque to the tires, and the car can start smoothly as the clutch is gradually lifted.