But surely ... surely, all of that flat-out killing of the engine (and the subsequent restart) has to speeding up the entropy of said engine, meaning that the fuel savings will be eaten up by mechanical problems.

I wonder if that's true. Hybrids do it all the time. The engine is warm for all the subsequent restarts, and oil should still be warm and coating most of the moving parts. I bet the restarts aren't so painful.

There's a particular hill in home town that my mamma used to drive on her way to work every morning. She'd kill her engine at the top of the hill and, if she started at the right speed, she'd coast almost 1.5 miles and come to stop at the stop light. It's a very peaceful experience - probably the most organic feeling while driving.

Just remember that your power steering and power brakes feel totally different and are much harder to operate with the engine off, so if you're going to do this, practice somewhere safe first; don't do it for the first time while barrelling down a switchback mountain road.

Particularly, the brakes become borderline-useless after one or two uses with the engine off. It's definitely dangerous to drive around in that condition.

That said, I've done it on a big hill in my area, not a steep one, but long enough to cover almost 3 miles without the engine running.

I don't believe he's getting 59 mpg. Basically everyone I know who's aware of their mileage inflates it a little bit. And anyone who is so aware of his own mileage as to be labeled a "hypermiler" probably inflates with the best of them.

And driving like it describes sounds like he's taking all the fun out of driving.

There are a series of three exits in my home town on uphill section of freeway. We used to try and see who could punch it the hardest from the top of one onramp and then coast to a stop at the top of the off ramp. The goal being to attain the highest speed possible and still coast to a dead stop at the top of the off ramp. Use of brakes during the run disqualified that run.

I started doing the coast to a stop with every off ramp and to this day when driving my '66 I can coast to a stop within feet of the stop sign on most off ramps.

The truck thing isn't saving fuel, it's stealing it from the truck. Depending on the car and truck the truck driver can even feel the car drafting. It can be extremely irritating.

This thread is enough to kick me out of lurk mode !

Most people don't realize that for most fuel injected cars or trucks of the past 20 years, if you're coasting down hill and are over 35 or 40 MPH with your foot off the pedal (also, stay in drive), your engine controller will go into decel fuel cut-off and turn off your injectors, using no fuel at all. This is to avoid overheating the catalytic converter.

Does this happen on automatic transmission cars, as well? I believe it with manuals, but with autos it seems like they drop into some kind of idle when you let off the gas.