Why do some people drive with their headlights on during the day?

Question

Two days ago, on my way to work, I noticed that many cars passing me by had their lights blaring in the day's underglow of the sun. Although several cars didn't have their lights on, every street I went down, I noticed how some people didn't and some people did. I would think that it saves battery power to drive with your lights off. I have never driven with my lights on before the sunsets, and don't understand why any one would.

I am only asking this question, because two days ago, is like the first time I ever noticed it and it peeked my curiosity.

Answer 1

so it's safer especially on cloudy, rainy days, or on mountain roads with reduced visibility. Cars have daytime running lamps, so some people decide to utilize it to prevent accidents.

Answer 2

People who drive during the daytime with their headlights on may want to reconsider that decision! The calculations below show that the vehicle's gas mileage is significantly reduced by having the headlights on!

During the night, and during inclement weather, it is necessary, and even legally required, to have the headlights on. No problem there! But there are millions of drivers who turn their headlights on during daytime driving, too. If that actually represents an additional safety factor, great! Other drivers who may not be paying attention might actually notice the movement of the bright headlights, and thereby avoid an accident. Only you can determine the possible value of this. (My personal solution to this has always been to simply drive really bright red cars, where people tend to notice them during the daytime whether the headlights are on or not!)

Modern automobile engines are promoted for their "200 horsepower" or even larger amounts. However, it will be shown below that a standard automobile only uses around 30 horsepower to move the automobile at highway speeds along a level Interstate Highway. (The extra horsepower is needed and used for acceleration and passing and for going up hills). It will also be shown that the vehicle's alternator must create the electricity for the headlights (and many other vehicle lights) and that as much as two horsepower of actual engine power is used for that purpose.

This means that a vehicle that would use 32 horsepower with headlights off might take 34 horsepower when the headlights are on. Essentially, this can result in the gasoline mileage being lowered by nearly 6%. In other words, you may wind up buying 6% more gasoline because of having the headlights on!

Answer 3

Some people own two cars where one has automatic lights that detect nighttime and another that doesn't, so they sometimes forget to manually turn off their headlights when driving the one that doesn't.

Answer 4

Driving with headlights on makes the car more visible, and supposedly safer.  I suppose it is the same reasoning behind motorcycles running with headlights on, for other drivers to notice them.

A lot of the newer cars have automatice daytime running lights, and the lights come on when the engine is turned on (unless the driver turns the lights off).

Answer 5

Many of today's cars are equip with daytime running lights that are for safety reasons so that you can see the cars coming down the road.

Answer 6

So your more visible to the oncoming traffic

Answer 7

If you are waiting at an entrance to a roadway, or you are at an intersection and it's foggy or raining, it would be obvious that you would see that grey or silver vehicle coming if it had headlights on, even during the day, right?

Well, you might see the SECOND car coming and miss the one in front of it, if that FIRST car doesn't have any headlights on during the daytime hours. Believe it or not, this is a very common occurrence.

Also make sure you check --left, right, left and then right , and left (never stop looking left and right until you have finished your turn) again after stopping, because that "A" pillar (front pass. side pillar) might block your view of a car coming. If you stop first and then look twice, you'll see that vehicle the second time you look, and you'll be glad you looked. This also happens more than you might think.

Daytime running lights must be installed on all new vehicles sold in Canada, and it has been that way since about 1991. These are a lower voltage headlight which automatically come on when the vehicle starts.

I hope that sheds more light on this subject for you [grin]

Answer 8

In some states use of lights is mandatory one hour before sunset until one hour after sunrise. It is a good idea to use your headlights on two lane roads where passing is done. It is much easier to see a car's headlights than the car itself. Also, some states have a law that makes headlight use mandatory when using windshield wipers. This is a good practice whether the law requires it or not. Also, during fog and other visibility-limiting events.

Regards,

Dan

PS It does not save battery power to use headlights.

Answer 9

I keep my lights on during the day just to be sure that I am being seen by other cars going on the road and getting out of their driveways, and especialy during the rain

I know in NY state when you put your wipers on you have to put your lights on, Anyway I think it should be mandatory to have daylights on cars in America like in Canada

Answer 10

In Canada and Sweden and possibly other nations, "daytime running lights" are required so some carmakers make them for all cars regardless where they are sold (standardization of manufacturing process). The lights come on automatically.  Daytime lights have been shown to decrease the number of accidents bc they make cars more easily seen.  Some ppl like me will turn on the headlights (no automatic lights) for this reason.  If you have ever driven in West TX, AZ, etc. where there is a lot of desert, many beige or silver cars are hard to see and the only thing you can see are the 2 points of light from the headlights. You should drive with your headlights on during the day.

Answer 11

First of all, driving with your headlights off doesn't save your battery...the battery doesn't power the car when it's running, the motor powers the alternator, which creates electricity while the vehicle is running. I spent a year in Iraq, and most of the Iraqis wouldn't turn their lights on AT NIGHT for fear of running down their batteries. :)

Secondly, cars are being made today to have lights that automatically turn on when the car is started. This is a safety feature, as you notice cars with their lights on more than you do cars with their lights off (you noticed them didn't you?). Sometimes people forget to turn their lights on when it is storming (even though it's daytime, it's dark and harder to see oncoming traffic)...this is the primary reason for daytime running lights.

Anyway, I'm not saying you should or shouldn't turn your lights on when you drive, just hoping to help answer your question.

Answer 12

DRL's (daytime running lights) are designed to make a car more visible even during the daylight.  Studies have proved their effectiveness, particularly in regions like Scandinavia where ambient light levels during the day are quite low.

Answer 13

most new cars these days have automatic lights that come on all the time...some may just want to be safer than sorry. As long as your car is on I dont think there lights being on will affect it. I see it all the time..its normal.

Answer 14

You will find that Volvo cars are made with the side lights coming on as standard, this made people aware that the car was present and in turn has reduced accidents with pedestrians, To a point you have answered your own Question, You have noticed the cars with their lights on !!!!

Answer 15

do you really have a mohawk haircut??

Answer 16

We have no choice...our car has daytime running lights and they are on all the time.  We have dims and brights as well, but these are on unless we turn the car off.