# LED Taillights **URL:** \ **Category:** Factual Questions\ **Created:** [May 27, 2003, 8:17am UTC](https://boards.straightdope.com/t/led-taillights/177730 "2003-05-27T08:17:24Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [May 29, 2003, 1:24pm UTC](https://boards.straightdope.com/t/led-taillights/177730/21 "2003-05-29T13:24:54Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > **I can’t imagine any engineer designing _that_ close to tolerance.** ::snerk:: I can. ---
**Author:** ![El\_Marko](https://avatars.discourse-cdn.com/v4/letter/e/58956e/32.png) [@El\_Marko](https://boards.straightdope.com/u/El_Marko)\ **Post date:** [May 29, 2003, 2:50pm UTC](https://boards.straightdope.com/t/led-taillights/177730/22 "2003-05-29T14:50:15Z")
Heh, me too. BTW, I’ve often thought over the years that it would be helpful to have brakelights that indicate the amount of pressure being applied to the pedal with variable intensity. That way it would be easier to tell if someone ahead of you was just casually riding the brake pedal or doing an emergency panic stop, or something in between. Seems like it would be fairly easy to do something like this with an LED array. Either you could vary intensity or the total number of lights that light up based on how far the pedal is depressed. Just a thought. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [May 29, 2003, 3:01pm UTC](https://boards.straightdope.com/t/led-taillights/177730/23 "2003-05-29T15:01:31Z")
The system you describe was sold as an after-market item during the eighties, **El Marko** , except that flashing frequency rather than light intensity was used to indicate pedal pressure. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [May 29, 2003, 4:56pm UTC](https://boards.straightdope.com/t/led-taillights/177730/24 "2003-05-29T16:56:32Z")
It’s even older than that. I’ve got a magazine from the late 50s or 60s which describes such a device. Also, I’ve seen a device which would flash the taillights when the driver removed his foot from the gas pedal. AFAIK, that’s never made it to mass-production. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [May 29, 2003, 5:10pm UTC](https://boards.straightdope.com/t/led-taillights/177730/25 "2003-05-29T17:10:51Z")
I remember seeing that same article. I think it was in _Popular Science_, predicting the wonders of the forthcoming automated highway system. “Drive onto the superhightway, push a button and relax! The car will do the driving for you!” As a general rule, if PS went gaga over some aspect of the bright new future, you could be pretty sure it was never gonna happen. I remember an article on powered exoskeletons (think Sigorney Weaver in _Aliens_) that my 8-year old self thought were about the coolest thing I ever saw…nope, never happened. PS also thought that “fluidics” would revolutionize the world with air-powered light switches and computers. Nope. Does anyone remember the “Rollamat”, the “only fundamental mechanism invented in the twentieth century”? An “S”-shaped piece of metal embedded between two rollers? Anyone? Anyone at all? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 29, 2003, 5:19pm UTC](https://boards.straightdope.com/t/led-taillights/177730/26 "2003-05-29T17:19:58Z")
The Rolla…_what_ now? What was this thing supposed to do? ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [May 29, 2003, 5:38pm UTC](https://boards.straightdope.com/t/led-taillights/177730/27 "2003-05-29T17:38:19Z")
My memory could be a little better. A little research and here we are: The “Rolamite”: [Frictionless Machines from Rollers & Bands](http://www.rexresearch.com/wilkes/1wilkes.htm#ps) ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [May 29, 2003, 5:53pm UTC](https://boards.straightdope.com/t/led-taillights/177730/28 "2003-05-29T17:53:46Z")
As I read through the article, I see a few relatively recent patents based on the concept…but the thrust of the Popular Science articles would have you believe that this would revolutionize the world. I gather that the rise of solid-state electronics made it easier and cheaper to do many of the things proposed for the Rolamite long before any of them were actually developed. The same thing happened with fluidics, I suppose… ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [May 31, 2003, 4:24am UTC](https://boards.straightdope.com/t/led-taillights/177730/29 "2003-05-31T04:24:18Z")
> [@](#): > > \*Originally posted by BrotherCadfael \* > \*\*As a general rule, if PS went gaga over some aspect of the bright new future, you could be pretty sure it was never gonna happen. \*\* Not necessarily. The original [Tucker Torpedo](http://www.grinitch.com/ida/images/drawing.jpg) was to have fender mounted headlights that turned with the wheels (this was later dropped in favor of having the center headlight turn). Lexus has just introduced such a system, some 57 years later. One of the magazines Tucker’s car was profiled in was PS, so maybe it only takes 57 years for something to go from the pages of PS to the real world.:dubious: ---
**Author:** ![something\_clever](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@something\_clever](https://boards.straightdope.com/u/something_clever)\ **Post date:** [May 31, 2003, 6:31am UTC](https://boards.straightdope.com/t/led-taillights/177730/30 "2003-05-31T06:31:35Z")
actually i read somewhere the military is toying with the powered exoskeleton… but they are waiting on a power source… coulda been a dream though… i have no idea where i saw that. ---
**Author:** ![Sock\_Munkey](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@Sock\_Munkey](https://boards.straightdope.com/u/Sock_Munkey)\ **Post date:** [May 31, 2003, 6:54am UTC](https://boards.straightdope.com/t/led-taillights/177730/31 "2003-05-31T06:54:39Z")
There are some articles and links for the powered exoskeleton on the how stuff works site. > **[HowStuffWorks - Learn How Everything Works!](https://www.howstuffworks.com)** > > HowStuffWorks explains thousands of topics, ranging from the flu to black holes to conspiracy theories, with video and illustrations so you can learn how everything works. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [May 31, 2003, 7:55am UTC](https://boards.straightdope.com/t/led-taillights/177730/32 "2003-05-31T07:55:52Z")
> [@](#): > > _Originally posted by BrotherCadfael \* > \*\* I remember an article on powered exoskeletons (think Sigorney Weaver in Aliens) that my 8-year old self thought were about the coolest thing I ever saw…nope, never happened._\* You know, now that I think about it, wasn’t there an Elvis movie that featured those things in a brewery of all places? ---
**Author:** ![vasyachkin](https://avatars.discourse-cdn.com/v4/letter/v/c5a1d2/32.png) [@vasyachkin](https://boards.straightdope.com/u/vasyachkin)\ **Post date:** [May 31, 2003, 8:12am UTC](https://boards.straightdope.com/t/led-taillights/177730/33 "2003-05-31T08:12:53Z")
the reason for using LED taillights (red stop lights) is this : led comes on instantly but incandescent bulb takes some time. this time difference may be the difference between life and death in an accident. why headlights are not used is simply that LEDs are still very low power. using an overly large cluster would probably be problematic to get correct dispersion pattern, and would probably be more expensive than HID which works just fine. HID though takes very very long time to turn on so can not be used in taillights. ---
**Author:** ![something\_clever](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@something\_clever](https://boards.straightdope.com/u/something_clever)\ **Post date:** [May 31, 2003, 8:25am UTC](https://boards.straightdope.com/t/led-taillights/177730/34 "2003-05-31T08:25:39Z")
remember the movie “dave”? “i once caught a fish… THIS BIG” btw you wouldnt want hid tail lights… that would be blinding. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 31, 2003, 1:21pm UTC](https://boards.straightdope.com/t/led-taillights/177730/35 "2003-05-31T13:21:47Z")
> [@](#): > > \*Originally posted by vasyachkin \* > **the reason for using LED taillights (red stop lights) is this : led comes on instantly but incandescent bulb takes some time. this time difference may be the difference between life and death in an accident.** No, this is just plain silly. The turn-on time even for incandescent lamps is orders of magnitude faster than the mean human reaction time. An LED that turns on in a microsecond isn’t going to make much of a difference versus an incandescent bulb that turns on in a hundredth of a second, when the normal human reaction time is about .25 second. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [May 31, 2003, 4:20pm UTC](https://boards.straightdope.com/t/led-taillights/177730/36 "2003-05-31T16:20:14Z")
I’ve never heard anyone tout the “slower speed” of incandescent lights before. If a micosecond makes the difference between life and death, then it just wasn’t meant to be. Good luck with eternal, endless oblivion. :eek: ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 31, 2003, 5:04pm UTC](https://boards.straightdope.com/t/led-taillights/177730/37 "2003-05-31T17:04:37Z")
I wasn’t touting anything. All I’m saying is the difference in turn-on time is meaningless in terms of the much slower human reaction time. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [May 31, 2003, 5:13pm UTC](https://boards.straightdope.com/t/led-taillights/177730/38 "2003-05-31T17:13:31Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*I wasn’t touting anything. All I’m saying is the difference in turn-on time is meaningless in terms of the much slower human reaction time. \*\* Umm…OK, that’s great. I was _agreeing_ with you. 😕 ---
**Author:** ![Big-Ole-Steve](https://avatars.discourse-cdn.com/v4/letter/b/4da419/32.png) [@Big-Ole-Steve](https://boards.straightdope.com/u/Big-Ole-Steve)\ **Post date:** [May 31, 2003, 5:15pm UTC](https://boards.straightdope.com/t/led-taillights/177730/39 "2003-05-31T17:15:12Z")
I agree, **Q.E.D.,** The real benefit of LED brake lights is that they look cool and possibly don’t burn out as much. I imagine Human reaction time kinda nullifies the benefit of faster lights… HOWEVER, one note, the NHRA (The sanctioning body behind Championship Drag Racing) recently changed the Christmas Tree’s (The starting lights) from Incandescent to LED. Hilarity ensued, where drivers, who had for 40 years become used to punching the gas as the incadecent lights faded up, were given the instantaneous “BLINK” of the LEDs and they would panic and give it gas too soon…Many drivers red-lighted (i.e. jumped the gun) and had to retrain themselves how to drive. (yeah, I know, lighted? But that’s how drag racer’s talk) Of course, those guys are super-human with their reaction times (Which is why they get to do it for a living) AND in that sport, winning and losing is done in thousands of a seconds, often…so those differences between incadesence and LED’s did provide impact. cite: [http://www.nhra.com/2003/news/January/013104.html](http://www.nhra.com/2003/news/January/013104.html) you can also read a driver complaing about not having the “fade” he was used to, here: [http://www.dragbike.com/news/04-03/041003d.htm](http://www.dragbike.com/news/04-03/041003d.htm) Umm, am I offtopic? Steve ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [May 31, 2003, 5:17pm UTC](https://boards.straightdope.com/t/led-taillights/177730/40 "2003-05-31T17:17:40Z")
Oh, I see why you’re confused, and rightfully so. I meant that I’ve never seen anyone tout that incandescent lights are slower than LEDs such that using LEDs can yield a savings in life from that few microseconds. Thus my comment on “if a few microseconds makes the difference…” The Board timed out when I made my post, and I didn’t end up typing the whole thing back in the second time. [Previous page](https://boards.straightdope.com/t/led-taillights/177730.md?page=1) [Next page](https://boards.straightdope.com/t/led-taillights/177730.md?page=3)