What Causes Vehicle Rollaway?
2 Answers
Vehicle rollaway occurs because there is a time interval between switching from the brake pedal to the accelerator pedal. Even after pressing the accelerator, it takes another time interval for the vehicle's driving force to increase enough to counteract gravity. The following are specific causes of vehicle rollaway: 1. Parking brake not engaged leading to rollaway: Failure to press or pull the handbrake causes the vehicle to roll due to inertia. 2. Insufficient power causing rollaway: Lack of power in neutral gear can also lead to rollaway. 3. Delayed power delivery causing rollaway: Some automatic transmission models experience delayed power delivery when releasing the brake and pressing the accelerator, which can also result in rollaway.
Rolling usually occurs when a parked car moves unexpectedly, and I've encountered this several times. The main reason is parking too casually on slopes. The most common cause is not fully engaging the parking brake, especially in older cars where the handbrake cable has loosened or rusted—once you release the foot brake, the car starts to slide. Additionally, in automatic transmission cars, if the gear isn't properly shifted into 'P' (Park), or if the slope exceeds the braking force, rolling can happen. From my own experience, parking lots can be very slippery on rainy days, and if the slope exceeds 5 degrees, extra caution is needed. To prevent this, I always make sure the gear is fully engaged, the handbrake is tightly pulled, and if I'm really worried, I use a rock to block the tires. In short, developing good habits can avoid trouble and protect both your own and others' safety.