So far as preventing daytime accidents.
It sounds plausible, but is there any reliable evidence to show that there are actually fewer accidents among people who keep their headlights on during the day?
I found this in a December 13, 1999 L.A. Times article
Well if the insurance company offers a discount for it, it has to help to have daytime running lights. It supposedly makes your car more visible, so nobody would not see you and then turn in front of you or something.
There was a commercial I saw once where everyone kept telling this guy his lights were on, and then it made a point about how the headlights on made people see the car coming.
My car has them standard, I can’t turn them off when the car is running. They just get brighter at night when I turn them on.
I HATE daytime running lights on cars, I’ve never understood them. On motorcycles it is a different issue but a car is huge and can be seen if you are actually LOOKING. I’ve driven cars with the running lights and the dash lights are always on, this leads for people NOT turing on their lights at all so you don’t get the rear running lights. I don’t know how many cars don’t turn on the rear lights, but I know that the older Geo Metros dont and I’ve seen plenty of people who drive down the road who haven’t turned on their lights. that’s my opinion I don’t think they do squat.
They probably have some benefit in odd lighting conditions, such as near sunset when the sun is still out but with trees or such casting shadows. They probably get attention while people aren’t used to them, but that will diminish as we adjust to expect headlights on all day.
The issue about failing to turn on the headlights is a good complaint - I drove a rental car and couldn’t figure out why they had a lights switch, but now it makes sense. Plus daytime running lights are typically set to run at a lower brightness.
I’m sure there are some numbers, but I don’t know where to find them.
BobT posted:
I’m curious how that’s supposed to work. The only way I can figure is that it would have to have the headlights aimed lower or something. If you make the lights brighter, that should send more light into the oncoming drivers’ eyes. Unless they’re focused better?
I don’t have an answer for the OP, but I will agree that they seem (to me at least) to be a good idea. This opinion is based on my observations that cars with them are easier to see (in general) than those without. Obviously, not everybody agrees on this.
But, I have a question. On cars equipped with daytime headlights, can they be turned off? When driving into a stargazing site, for example, the generally accepted rules of etiquette entreat you to turn your headlights off and come in on parking lights only, to minimize damage to the night vision of people already there. If my car has daytime headlights, can I comply? Or is there no way to have the engine on without either the day or night headlights being on?
I do realize that, strictly speaking (at least in CA), driving with only your parking lights on is illegal. I suspect that this very argument is used on occasion to put down (or at least trivialize) the objection I just made.
Those who have daytime headlights - what’s the scoop?
I think that’s exactly it. They are, in theory, focused more tightly (and uniformly). Essentially, the area of illumination is the same, but the brightness profile is more uniform within that patch - less tailing off as you get away from the center. It’s supposed to be much more of a top-hat profile.
Brad: I don’t know about all cars, but I own a 1996 Pontiac Grand Am with daytime running lights which I can’t turn off. I don’t mind the lights most of the time, but I hate it that I can not turn them off ever! I often take a short cut home via Camp Lejeune Marine Corps base. At night you are suppose to use parking lights only when going through the gate so that you don’t blind the sentry. I can’t turn my lights off so I always feel like they think I am being rude.
I also have noticed the same problem that Edward mentioned. I drove the car at night for several months before I realized that my rear lights didn’t come on unless I actually turned the head lights on. Since they always seemed to be running I never even thought about it.
I belive so, but it’s permanent, as it entails cutting the wire that tells the lights to go on when the engine is running, but not when the headlight switch is in the on position. I suppose you could rig up an extra switch if you knew which wire it was.
For driving near stargazing areas and the like, pull the emergency brake up one notch, that’ll turn the DRLs off.
That’s right, I completely forgot that. I was parked on an incline once with the emergency brake on and when I started the car I noticed the lights didn’t come on until I released the EB.
Not on all of them. Even then, usually that would only work starting off from starting the engine the first time. Once they are on I know on my vehicle the only way they are going off is shutting down the engine.
Eric
I disagree. I find them to be very glare-y. Perhaps some of the cases are due to misaligned headlights.
A recent Car Talk Column discussed these high-intensity lights.
They say that the NHTSA opinion is that the real problem is cheap aftermarket knockoffs, which are really bright but poorly focused.
this site says that studies in Scandinavia show that daytime running lights can reduce multi-vehicle accidents by up to 32%. But the same article discusses a Canadian study that show the danger of masking: a car without running lights surrounded by cars with them is relatively difficult to see.
this site links to 4 studies, 1 that comes down in favor of running lights and 3 opposed.
Thanks for the info on the daytime headlights. It sounds like things are as I had feared, at least on some vehicles.
My beloved pickup does not have DHL’s, but it does have a dome light that cannot be disabled (short of removing the bulbs or other trickery). I hadn’t really realized this until I pissed some people off at a dark site. :0
I just wanted to sneak in here and comment on HIDs. Please do not confuse HID systems (High Intensity ?Displacement?) with hyper white/blue bulbs. To my knowledge, only luxery cars so far have HID systems. So when you see those little imports or muscle cars with ugly glaring lights, they DO NOT have a HID system*. Look at a Lexus or Bimmer and you will definetly notice the difference between the two. I just wanted to defend HID systems in general. Thanks
-N
*A true HID system conversion for a car is in the thousands on dollars. So while it is possible that someone would covert their system to HID, in reality I find it HIGHLY unlikely.
Edward the Head wrote that a car is a huge, and therefore unmistakable object. He figures they don’t need DRLs for that reason. I respectfully disagree. My wife’s '92 white Bonneville was hit 6 times by motorists who all said they didn’t see it. The sixth one, in a Ford Exploder, drove across a four lane highway to total the Bonneville. She didn’t see it. The '98 Bonneville Mrs. Nott has now is equipped with DRLs, and I think it helps to distinguish the car from trees and rocks, which have no lights (except around Christmas.)
I remember being taught in a college course (a long time ago) that the initial study that proved the value of daytime running lights was done by the Greyhound Bus Company. They decided that they would run their buses for a full year with their headlights on full time. During that year, accidents dropped significantly (I remember about 30%, but I could be wrong). After the year was done, they decided to turn the lights off during the day for the next year to determine whether the lowered accident rate was a fluke. That second year accidents went right back up to the level they were before.
In response to Billdo’s post, I did a quick net search.
The National Motorists Association, whose motives I seriously question based on some of their other positions, claims that DRL’s have no benefit, and even makes reference to the Greyhound thing. NMA vaguely mentions that “a subsequent study” was done that contradicted Greyhound’s results. They then go on to advocate that DRL’s be banned. The overall tone of their article is pretty inflammatory to me, and I’m not sure how much faith to put in it.
This page has an extensive bibliography of studies. It claims to have both pro- and con- studies, but if one looks, there don’t actually seem to be an cons listed. Hmm… There’s also a link to a list of pro’s and con’s on the same site. The tone of this website towards them seems resoundingly positive.