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What, if any, benefit can be gained by selecting neutral in an automatic car rather than leaving it in drive when sitting for sustained periods at traffic lights.

My understanding is the vehicle will use less fuel. Also, in the event of a rear end collision, and the drivers foot slips from the brake to the throttle, the car is not going to accelerate into the rear of the vehicle in front.

I would be pleased to receive your comments.

Dave

From the "Ask Jack" archives - 2 February 2009

The amount of fuel saved by placing the transmission in neutral would be minimal if any at all, in my opinion. Leaving the transmission in gear also helps reduce wear and tear on the internals by not having to reduce and apply oil pressure constantly and unnecessarily.

If fuel saving is the goal, I believe adopting smooth throttle control when driving is ahead of placing the transmission in neutral at the lights.

I am not aware of any accident statistics which highlight the increase in risk by leaving the transmission in 'D' in stopped or queued traffic.

Hi jbiddle,

Just from the view of mechanical protection (whatever to reduce wear/tear, or save the break), for an automatic car waiting at the traffic light for 1 minute or longer, which transmission gear is preferred? "D" or "N"?

Thanks.

Leaving the transmission in "D" will help reduce mechanical wear and tear. However if you are stuck in a traffic jam for several minutes, its sensible to shift to "N" and take your foot off the brake (but apply the handbrake).