Dear Umbra,

I have a question about getting the most miles per gallon. If you put your car into neutral at stops or going downhill, do you save any gas? My car is an automatic.

Verona, N.J.

Reader support helps sustain our work. Donate today to keep our climate news free.

Dearest Jeff,

Grist thanks its sponsors. Become one.

Another great question we have all pondered. Louisa and her fellow mechanics thought you might save a little gas. Let me be more specific: a very, very small amount of gas. Droplets.

In the final cost-benefit analysis, those droplets you save cannot compare to what you risk. Should you suddenly need to execute an accident-avoiding maneuver while coasting in neutral, you would be hosed. (That’s a technical automotive term.) A variety of horrifying things might happen, to wit: Getting back into gear would occupy the split second you had to avoid the accident. Or you would successfully get back in gear, only to realize that your engine had died while you were in neutral and that your brakes and steering had locked. Or that your brake fluid had superheated, rendering your brakes useless.

Coincidentally, coasting in neutral is illegal in many states.

Putting it in park at a stoplight seems to pose no danger. Plus, it’ll save you a wee bit o’ gasoline. Go to town!

Grist thanks its sponsors. Become one.