Should Automatic Transmission Cars Shift to Neutral at Traffic Lights?

[PiperLee]

Automatic transmission cars should shift to neutral when waiting at traffic lights, and using the handbrake will provide additional safety. More detailed information is as follows: 1. Waiting at traffic lights in D gear with the foot brake engaged causes the passive wheel in the torque converter between the engine and transmission to remain fixed, generating a reaction force on the driving wheel, which increases the engine load. This can be understood as hindering engine operation. As a result, the engine ECU increases fuel injection, leading to higher fuel consumption, which is why you can see a high instantaneous fuel consumption when braking to a stop. 2. It is not recommended to wait at traffic lights in P gear because shifting from P to D gear can sometimes cause the car to reverse, affecting the vehicle behind and potentially leading to a rear-end collision, for which you may also bear some responsibility. 3. Some vehicles now come with an "autohold" function, which is an automatic handbrake. After pressing the button to activate this function, the car will automatically brake once it comes to a stop, eliminating the need to shift between reverse and drive gears, and the vehicle will remain in a parked state. However, not shifting to neutral still poses certain safety risks, such as the car accelerating rapidly if the accelerator is mistakenly pressed, which could lead to a collision. Additionally, the auto start-stop function is also suitable for use at traffic lights, as it helps save fuel to some extent, and the engine, when turned off, does not emit exhaust fumes into the car.

[DiWalker]

I've been driving for many years, and generally don't need to shift to neutral (N) when waiting at traffic lights with an automatic transmission. Keeping it in drive (D) while pressing the brake is the most convenient, as you can just step on the gas when the light turns green without having to shift again. Shifting to N stops the torque converter from working, which theoretically reduces minor wear and saves a tiny bit of fuel, but modern automatic transmissions are designed to be very smart, and short stops like a 30-second red light won't cause any issues at all. Shifting to neutral also requires remembering to engage the handbrake to prevent rolling, which is much more troublesome. I think keeping it in D for everyday driving is fine—it's worry-free and effortless. If the red light is particularly long, like over a minute, you might consider shifting to N to give your leg a rest, but make sure it's safe. Don't underestimate these habits; over time, they can help protect your transmission's lifespan.

[LilahMarie]

As an average car owner, I don't like fiddling with shifting to neutral at red lights. Keeping it in D gear while braking is simple and quick, allowing seamless acceleration when the light turns green. Automatic transmissions are designed with stop scenarios in mind. Although shifting to N gear might slightly reduce engine load, the fuel savings are negligible. I've compared both methods and found almost no difference in fuel consumption when waiting in D gear. On the contrary, shifting to neutral risks forgetting to engage the handbrake or causing delayed starts. From a safety perspective, it's more important to stay in D gear with your foot on the brake - this allows quicker reaction if rear-ended. Remember, safety comes first when driving - don't take risks for minimal fuel savings. Cars are tools - the more intuitive the operation, the better. There's no need to overcomplicate small things.

[LillianDella]

I'm used to keeping the car in D gear and stepping on the brake after stopping at traffic lights, which is both efficient and safe. Shifting to neutral N gear might seem fuel-saving, but the actual effect is minimal. Modern automatic transmission vehicles manage the engine well in D gear during short stops. Shifting to neutral requires an extra step—it's unnecessary for short red lights, and while occasionally useful for long ones, don't rely on it. Comfort is more important; keeping it in D gear might tire your leg slightly, but you'll get used to it. The key is to avoid accidentally shifting to P gear, as that can damage the transmission more. With 20 years of driving experience, I've never seen anyone have issues from using neutral, but simplicity beats complexity.