Whether to leave the car in Drive (D) or shift to Neutral (N) while waiting at a red light for safety and fuel efficiency is something not all drivers are aware of.

Reader’s Question:

I have been driving for over 10 years and currently use a Honda Civic with an automatic transmission. Normally, when stopping at a red light, I keep the car in Drive (D) and hold the brake. Once the light turns green, I simply release the brake and move forward.

However, many times when driving friends around, they have told me that I should shift to Neutral (N) and engage the parking brake while waiting at a red light. They claim it is safer, reduces wear on the car, and saves fuel. So, which method is actually correct?

Answer:

When stopping at a red light in an automatic car, you have three possible gear options:

1. Keeping the Car in Drive (D) and Holding the Brake

By keeping the car in D, the vehicle is always ready to move once you release the brake. This provides better responsiveness in emergency situations, such as if the car behind you loses control, or if you need to inch forward slightly.

Drawbacks:

• Holding the brake for a long time can be tiring for your foot.
• If you're distracted and accidentally release the brake, the car may move forward unexpectedly. In a panic, you might press the wrong pedal (such as the accelerator instead of the brake), leading to a potential accident.

2. Shifting to Neutral (N) and Engaging the Parking Brake

This option allows you to rest your foot and is believed to reduce fuel consumption slightly. When in Neutral, the car is technically running in an idle state, consuming less fuel than when in Drive. However, modern electronic fuel injection systems automatically reduce fuel flow when the accelerator is released, meaning the fuel savings are minimal.

Precautions:

• You must engage the parking brake to prevent the car from rolling forward or backward.
• When the light turns green, you need to press the brake pedal, release the parking brake, and shift back to Drive (D) before moving, which requires extra steps.
• Being in Neutral (N) makes the car less responsive in emergency situations where quick movement is needed.

3. Shifting to Park (P) and Releasing the Brake

This is another option if you want to fully relax your foot. The car will remain stationary without requiring the parking brake because the transmission itself prevents movement.

Considerations:

• This option is only practical for long red lights.
• Constantly shifting between D and P may cause extra wear on the transmission in some cars.
• Not recommended in stop-and-go traffic, as shifting from P to D takes more time and effort.

Final Recommendation:

• For short red lights (under 30 seconds): Stay in Drive (D) and hold the brake for quicker reaction time.
• For long red lights: Shift to Neutral (N) or Park (P) to rest your foot, but remember to engage the parking brake if in N.
• The difference in fuel savings among these options is negligible, so comfort and safety should be the priority rather than fuel efficiency.