Should Automatic Transmission Cars Shift to Neutral at Traffic Lights?
2 Answers
Automatic transmission cars should shift to neutral at traffic lights, and using the handbrake will be safer. Shifting to N (neutral) and applying the handbrake can save some fuel because the passive wheel in the torque converter of the transmission is in an idling state at this time, which does not increase the engine's operating load, thereby reducing fuel consumption. It is not recommended to use P (park) at traffic lights because shifting from P to D (drive) can easily cause a reverse movement, which may affect the vehicle behind and, in severe cases, lead to a rear-end collision. Of course, the driver would also bear some responsibility. Using D (drive) with the foot brake at traffic lights is also not ideal, as the passive wheel in the torque converter between the engine and transmission is fixed, creating a counterforce that acts on the driving wheel, increasing the engine's load. This can be understood as hindering the engine's operation, causing the engine ECU to increase fuel injection, leading to higher fuel consumption.
I always drive an automatic transmission car, and when encountering a traffic light, I keep it in D gear and step on the brake. This is the most convenient and quickest way. As soon as the light turns green, I can go without needing to shift gears again, putting safety first to avoid rear-end collisions. In the city, red lights are short, and frequently shifting to N gear is tiring and prone to operational errors. Although shifting to N gear can save a little fuel and reduce engine load, modern car transmissions are very durable, and short-term idling in D gear is fine. I think keeping it in D gear is the most worry-free habit, especially for beginners who might panic easily—focusing on the road is more important. Never shift to P gear while waiting at a light; if rear-ended, it could damage the transmission. Overall, balancing safety and efficiency is key—don't take risks just to save a little fuel.
