Should You Shift to Neutral When Waiting at a Red Light in an Automatic Car?
3 Answers
When waiting at a red light in an automatic car, shifting to neutral and engaging the handbrake is safer and more fuel-efficient. In neutral with the handbrake on, the passive wheel in the torque converter of the transmission idles without adding resistance to the engine operation, thereby reducing fuel consumption. If you wait in D (Drive) gear with the foot brake applied, the passive wheel in the torque converter remains fixed, creating a counterforce on the driving wheel that increases engine load, effectively hindering engine operation. Some modern vehicles feature an autohold function (automatic handbrake) that automatically applies the brakes when the vehicle comes to a stop, eliminating the need to shift from reverse or drive gears while maintaining the parked state.
As someone who has driven for many years, I always recommend keeping the car in D gear and stepping on the brake at red lights—it's simple and safe. The vehicle won't roll unexpectedly, reducing the risk of accidents. Automatic transmissions are designed for idling conditions; keeping it in D gear ensures stable engine operation with minimal fuel consumption, while frequently shifting to neutral increases transmission wear. For short waits, there’s no need to complicate things—staying as is is the most hassle-free. Especially in city driving, where traffic lights change quickly, staying in D gear allows for smoother acceleration. Once you develop this habit, driving becomes more relaxed and efficient while avoiding unnecessary mechanical wear. Safety first—always keep your foot on the brake, as any experienced driver would advise.
I usually pay close attention to fuel consumption and environmental protection when driving, so I've specifically researched this issue. When waiting at a red light, keeping the car in D gear while stepping on the brake is more fuel-efficient, as the engine intelligently reduces load in D gear, resulting in lower fuel consumption. Shifting to neutral, on the other hand, causes the engine to consume extra energy to maintain idle speed, which isn't cost-effective. For short waits like a few dozen seconds, staying in D gear is sufficient—less operation means more convenience and reduced exhaust emissions. For longer waits, you can shift to N gear to relax, but remember to engage the handbrake to prevent the car from rolling. If your modern car has an auto start-stop system, the engine will automatically shut off and restart when in D gear, providing even better energy-saving effects. In summary, from an energy-saving perspective, prioritizing D gear is beneficial for both the environment and your wallet.
