Roller coaster
My Brazilian wife was taught to put the car in neutral when going downhill, to save burning fuel needlessly. Over here we are told that's unsafe - since you have less control. You decide...
(moon monkey is busy making memories worth repressing, Mon 14 Nov 2011, 11:09, 2 replies)

Don't think it makes any difference.
If the throttle isn't being pressed, there's no more fuel going into the engine anyway.

Strangely enough, one of the worst drivers I have ever come across for this was a Brazilian schoolfriend of my wife (also Brazilian). He had this bizarre way of driving, he'd put his foot flat to the floor for 5 seconds, then lift off for 5 seconds, then repeat.

It was very uncomfortable as a passenger, and presumably terrible for fuel economy.
(username failed moderation, Mon 14 Nov 2011, 11:32, closed)

I was told that coasting down a hill uses more fuel (the amount of fuel in neutral to keep the engine running) but rolling down the hill in gear uses no fuel at all as long as your foot is off the throttle.
(tyrellsOwl, Mon 14 Nov 2011, 13:26, closed)