Will an automatic transmission car roll when parked in P gear?

[SanCamilla]

No, it will not roll. Here is the relevant introduction: P gear: The P gear position has a locking device that locks the gear, which can provide a certain anti-slip effect on the vehicle. However, its locking force cannot compare to that of the handbrake. If parked on a slope without engaging the handbrake, the P gear can create pressure on the internal components of the transmission, potentially causing structural damage. Automatic transmission: As the name suggests, an automatic transmission does not require the driver to manually shift gears. The vehicle automatically selects the appropriate gear based on driving speed and traffic conditions. Generally, automatic transmission cars have six gear positions, arranged from top to bottom as: P, R, N, D, S, L.

[Susanna]

I've been driving for over a decade. In an automatic transmission vehicle, putting it in P (Park) on level ground basically prevents rolling because it locks the transmission, thus securing the wheels. However, this isn't entirely reliable when parked on a slope. Once, I parked on a hillside, engaged P, and shortly after getting out, the car slowly slid a short distance, which was quite alarming. Later, I learned that while P is designed to prevent rolling, on steep slopes the gravitational force can be too strong, making P alone potentially unreliable and possibly damaging to the transmission. Now, I've developed a habit whenever I park: first, stop the car firmly with the brake, shift to P, then engage the handbrake to ensure it doesn't move before feeling at ease. This method is the safest, avoiding unexpected risks. Parking safety is crucial, especially when traveling with family—small actions can prevent big troubles. In summary, P can prevent rolling, but it's not flawless; using it in combination with the handbrake is an essential skill.

[TheoLee]

From a mechanical perspective, the P (Park) gear in automatic transmission vehicles has a dedicated locking mechanism. Once engaged, it locks the transmission gears, preventing the vehicle from rolling. However, on uneven or sloped surfaces, gravity can exert excessive force on the P gear, potentially causing slight movement or even internal component damage. I recommend firmly pressing the foot brake when parking, immediately engaging the parking brake as an additional safety measure after shifting to P. Older vehicles require extra caution—for example, worn locking teeth may cause P gear failure and rolling. Regular maintenance can prevent such issues. Overall, the P gear is designed to prevent rolling and is safe for normal use, but don't rely solely on it. Engaging the parking brake adds an extra layer of protection for your vehicle and safety.

[SanLilliana]

As someone who prioritizes driving safety, I want to point out that while putting an automatic transmission in Park (P) can theoretically prevent rolling, unexpected situations often occur in real parking scenarios. Especially when parking on slopes or inclines, relying solely on the P gear isn't strong enough—gravity can cause the car to gradually slide. I once parked on a garage slope using only the P gear and nearly caused a minor accident. Therefore, the correct procedure is: after parking, first engage the P gear to stabilize the position, then use the foot brake or handbrake to lock the wheels for double security. This ensures the car won't move before you leave it. Safety first—never skip this step out of laziness. In summary, the P gear is a great assistant, but on complex terrains, it should be used in combination with the handbrake.