Dear Tom and Ray:

I have heard that the gasoline engines in hybrid cars run intermittently as needed to charge the battery and provide extra oomph. I've also always heard that stop-and-go driving is harder on cars than freeway driving. Does this mean we should expect shorter engine life from hybrid cars? Hope you're curious about this, too! -- Bill

TOM: Actually, Bill, it never crossed our minds until we read your letter. But then again, not much does cross our minds!

RAY: The answer is no, Bill. We should not expect shorter engine life from hybrid cars. Here's why.

TOM: When we talk about stop-and-go driving, it's starting the CAR -- making a ton and a half of metal move from a dead stop -- that is hard on the engine and drive train. It's not starting the ENGINE that causes extra wear and tear.

RAY: A hybrid car doesn't accelerate away from a stoplight any more often than any other car you drive.

TOM: Also, there are two basic types of hybrids. There's the Toyota approach, which uses the battery to get the car moving and then kicks in the gasoline engine to add power as the car needs it. That, obviously, should produce LONGER engine life, since the gasoline engine rarely needs to be used from a stopped position.

RAY: The other type is the Honda model, where the gasoline engine is used just like in any other car, and the battery-powered motor is used to boost acceleration when needed. But again, that's no different from how any other car uses its gasoline engine.