Headlights on during daylight hours? See what Tom and Ray say.

Dear Car Talk

Dear Car Talk | Aug 01, 2010

Dear Tom and Ray:

I enjoy your column every week. In our cars, the headlights turn off automatically when we exit the vehicle, so there's no danger of leaving the lights on and draining the battery. So my wife and I just leave the headlights on all the time when we're driving. I think if anything, this is safer, as does she. Is there any reason not to drive with the headlights on all the time? What about the fog lights? Unless you have a reason not to, we'll continue to do it. Thanks.

-- Rob

TOM: The only real downside is that you'll have to replace your headlight bulbs more often.

RAY: But if you're willing to pay that price for the additional visibility you get, you're certainly not doing any damage to the car.

TOM: It does take a little bit of energy to power the headlights, and that energy ultimately comes from the gasoline. So your mileage will be reduced by a very small degree. It might not even be measurable to you, but it will make a small difference.

RAY: All of this applies to the fog lights and driving lights, too. I would caution against leaving auxiliary driving lights on, because they're often the equivalent of your bright lights. That'll just annoy oncoming drivers, and they'll crash into you on purpose, negating the enhanced safety you get from the lights.

TOM: But we agree with you -- driving with your lights on is safer. The easier you are to see, the more likely that other drivers will see you. And if you're willing to pay the price in bulbs and gas mileage, light it up, baby.

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