Like a lot of cars these days mine is equipped...

Dear Car Talk

Dear Car Talk | Jun 01, 1994

Dear Tom and Ray:

Like a lot of cars these days, mine is equipped with cruise control. I use it a lot on the highway. My question is, when I hit the brakes and slow down while using cruise control, is it better (in terms of economy and wear and tear) to hit RESUME immediately, or use the accelerator pedal until the car is nearly back to its previous speed, and THEN hit the RESUME button? Hope you can enlighten me. Thanks!

TOM: It's great to know that there are people who have nothing better to do than to contemplate weighty issues like these Are you retired, Chad? Or are you just a college professor?

RAY: Actually, I've thought about this myself. And the answer is that, to minimize wear and tear and maximize economy, you should not use the "resume" button. We describe in our pamphlet "Ten Ways You May Be Ruining Your Car Without Even Knowing It" (if you don't have a copy, you can get one by sending $3 and....) that hard acceleration is one of the things that ruins cars. And when you hit the "resume" button from a substantially lower speed, that's exactly what you get; hard acceleration.

TOM: On most cars, when you tell the cruise control to "resume" its former speed, it assumes that you want to get there as quickly as possible, and it "floors it." That's fine if you're feeling impatient. But it's a waste of gas and an unnecessary strain on the drive train.

RAY: So accelerating more gently until you reach cruising speed, and then re-engaging the cruise control is the preferred method, Chad. And by the way, we expect to be cited in your upcoming scholarly paper on this subject.

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