Which gear should an automatic car be in when waiting at a red light?
4 Answers
If the waiting time is more than 40 seconds, shift to N gear and apply the handbrake. For less than 40 seconds, simply keep your foot on the brake in D gear. Here are some additional details about automatic transmission cars: 1. Heavy traffic: In cases of severe traffic congestion, it is recommended to shift to P gear. For brief stops, you can shift to N gear and apply the brake, depending on the situation. 2. Working principle: Automatic transmission cars typically use a hydraulic transmission device to replace the mechanical clutch found in manual transmission cars, hence there is no clutch pedal. When the engine speed is low, the torque transmitted by the fluid is limited and insufficient to move the car forward. When the gear lever is moved to the drive position and the brake pedal is released, increasing the throttle and engine speed raises the transmitted torque, propelling the car forward.
When waiting at a red light, I choose between putting the car in N gear or keeping it in D gear while pressing the brake. It depends on the duration of the red light and road conditions. For short red lights, keeping it in D gear and pressing the brake is the most convenient—quick to start, no need to shift back and forth, which is ideal for city traffic congestion. However, for longer waits, such as over 30 seconds, I shift to N gear to reduce the burden on the brakes, give the transmission a rest, and prevent overheating or premature wear. Additionally, from a safety perspective: although P gear locks the car, if a rear-end collision occurs, it could damage the transmission, so N gear carries relatively less risk. Of course, if you keep pressing the brake in D gear for too long, your leg may get tired, making N gear a more relaxed option. Overall, most drivers are accustomed to pressing the brake in D gear, but developing the habit of switching based on timing can make driving more comfortable and efficient.
I usually just leave it in D gear and hold the brake at red lights, rarely shifting gears, because it's convenient and quick. Shifting to N or P gear for short stops is actually more troublesome—you have to quickly shift back to D when starting, which can be flustering, especially for beginners. Keeping it in D gear while holding the brake maintains stable engine operation, ensures quick response when starting off, and avoids traffic jams. If the red light is exceptionally long, like at a railroad crossing, I might occasionally shift to P gear to rest, but generally, D gear is sufficient. This practice comes from years of urban driving experience: simplicity equals efficiency. Just be careful not to release the brake, or the car might lurch forward, which is unsafe.
When waiting at a red light, I prefer to shift to N gear, mainly to protect the car's mechanical components. Engaging N gear disconnects the transmission, reducing engine load and making the gearbox more durable, especially for older cars or frequent stops. For example, in congested areas, repeatedly waiting at red lights in D gear while pressing the brake can accelerate brake pad wear over time; shifting to N gear avoids this. For short red lights, D gear is fine, but N gear is more energy-efficient—slightly saving fuel, reducing emissions, and being more eco-friendly. Safety-wise, if hit from behind, N gear causes less damage than P gear. I usually check the red light duration: if shorter than 20 seconds, I stay in gear; if longer, I shift to N. After forming this habit, the car runs smoother.
