Design Rationale for DRL Behavior
Lexus Fanatic
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From: Maryland
Originally Posted by mmarshall
The laws do mention headlights with wiper-use, but they don't mention taillights. DRLs, on most vehicles, use the same bulbs as regular headlights (without taillights), and give the same effect as headlights....at a somewhat lower intensity. In fact, I asked a Virginia State Trooper about that, because, at first, I found the law somewhat confusing, too.
It's really not confusing at all, "wipers on, headlights on" since DRLs are not headlights, they don't qualify.
Last edited by SW17LS; Jul 16, 2017 at 10:21 AM.
Lexus Champion
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From: Canada
Both reasons given are legitmate reasons.
On vehicles that have separate bulbs for indicators and DRLs (as in cars with incandescent bulbs), it may be difficult to differentiate and distinguish turn signals from daytime running lights -- for any number of reasons, including how close they are together, and the exact colour of the DRL and indicator -- so the white DRL switches off when the amber indicator is on.
On vehicles that share bulbs, as in new LED DRLs, they cannot show 2 different colours at once. Colour-changing LEDs actually use 3 differently-coloured LEDs together -- mixing and matching red, green and blue -- to generate all possible colours. To produce white, all 3 LEDs are on. To produce amber, the blue LED is turned off, red is on full intensity and green intensity is dialled back.
On vehicles that have separate bulbs for indicators and DRLs (as in cars with incandescent bulbs), it may be difficult to differentiate and distinguish turn signals from daytime running lights -- for any number of reasons, including how close they are together, and the exact colour of the DRL and indicator -- so the white DRL switches off when the amber indicator is on.
On vehicles that share bulbs, as in new LED DRLs, they cannot show 2 different colours at once. Colour-changing LEDs actually use 3 differently-coloured LEDs together -- mixing and matching red, green and blue -- to generate all possible colours. To produce white, all 3 LEDs are on. To produce amber, the blue LED is turned off, red is on full intensity and green intensity is dialled back.
Lexus Fanatic
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From: Virginia/D.C. suburbs
Mike, DRLs are not headlights. When headlights are on, tail lights are on. You can't turn the headlights on without turning the tail lights on. Laws require headlight use when wipers are being used. Again, DRLs are not headlights. Read the links and stop arguing a position that we both know isn't true.
It's really not confusing at all, "wipers on, headlights on" since DRLs are not headlights, they don't qualify.
It's really not confusing at all, "wipers on, headlights on" since DRLs are not headlights, they don't qualify.
Lexus Fanatic
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From: ON/NY
All this arguing, come on everyone. People need to do some research. Luckily Jalopnik did it for us.
http://jalopnik.com/heres-why-modern...hen-1792394567
http://jalopnik.com/heres-why-modern...hen-1792394567
CL Community Team
Joined: Aug 2006
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From: San Francisco, CA
It's almost a moot point if you leave the headlight control on AUTO, like I do most of the time. Buick's system (can't speak for Lexus) system switches back and forth automatically from full-headlights to DRLs depending on ambient light conditions outside the car.....you'll notice that going in and out of a tunnel, for instance. It also varies the brightness of the video screen on the dash.
CL Community Team
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From: San Francisco, CA
Lexus Fanatic
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Lexus Fanatic
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From: Maryland
Originally Posted by LexsCTJill
Only Toyota that I am that does this is the Toyota Sequoia.
Lexus Champion
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From: SoFlo
Originally Posted by SW15LS
I'm surprised the Sequoia does that. None of my Lexus cars have ever done that which is really frustrating. Jeeps did, my Kia does too.
Lexus Fanatic
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From: Virginia/D.C. suburbs
I see a lot of vehicles every day every day with one-eyed Cyclops front ends while the turn-signals are operating. Under the conditions we usually drive in, here in the greater D.C. area, which is very well-lit-up even late at night, I don't think it's a big deal, since, even with only one light up front working, the roads and streets around here are so well-lit at night that visibility is usually not an issue at all. But, in rural or only dimly-lit areas, I can see where it might annoy some drivers...or even contribute to visibility problems, if you are dealing with a pitch-black or only lightly moon-lit environment, and you lose one of your front headlights while the blinkers are on.
Lexus Fanatic
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From: Maryland
Originally Posted by mmarshall
I see a lot of vehicles every day every day with one-eyed Cyclops front ends while the turn-signals are operating. Under the conditions we usually drive in, here in the greater D.C. area, which is very well-lit-up even late at night, I don't think it's a big deal, since, even with only one light up front working, the roads and streets around here are so well-lit at night that visibility is usually not an issue at all. But, in rural or only dimly-lit areas, I can see where it might annoy some drivers...or even contribute to visibility problems, if you are dealing with a pitch-black or only lightly moon-lit environment, and you lose one of your front headlights while the blinkers are on.
Again, DRLs are not headlights. Some carmakers shut off one DRL when the turn signal on that side is active, nobody shuts off a headlight.
Lexus Fanatic
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From: Virginia/D.C. suburbs
Yes, you are correct. I was referring to DRLs shutting off with the turn-signals, not the full-headlights.......a typo on my part. So disregard the comment I made about about night-use.
My new Lacrosse will probably be like that. Unlike my past cars, it has HID/Xenon full-headlights and a vertical LED light-bar.
Lexus Fanatic
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From: ON/NY
My opinion on the DRL that turn off when the turn signal turns on is that it's part marketing. It seems to m that it is party marketing in a look at me type of thing. Never been a big fan of it. But I am sure for the Chyster and Audi fans, it is something cool.