# I pit those who don't know when the fuck to turn on their headlights **URL:** \ **Category:** The BBQ Pit\ **Created:** [September 21, 2013, 6:10am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368 "2013-09-21T06:10:42Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 23, 2013, 4:46am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/41 "2013-09-23T04:46:14Z")
I never bother to turn my headlights on, there’s plenty of street lights, why waste my electricity? (I drive a Volvo, the headlights are pretty much always on, 24/7) ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 23, 2013, 4:50am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/42 "2013-09-23T04:50:41Z")
> [@flatlined](#): > > **Rick** , dude, I’m sorry. I wasn’t bringing up glurge, just offering some advice from my days living in the land of flash floods. Hitting a sudden localized storm at 50 mph can get all of the tires off the road and the car shimmies. In my experience, there was never any worries about being in god’s hands. It was just really unsetteling, so its something I do automatically now. > > Kinda like how I aways have my lights on and why I have flags mounted on my bike and wear fringe when I’m riding. I want people to see me. What’s interesting, we were handing out some reflectors and stuff to some bicyclists (San Jose Bike Party, kinda like Critical Mass but less assholes\*), and there were a group of them with fixies, they were all wearing black on black with black highlights, nary a one had any lights or reflectors. One said “You can’t hit what you can’t see.”\* and he was serious. \* and people wonder why drivers hate cyclists. - which is pretty damn easy ---
**Author:** ![Cat\_Whisperer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cat_whisperer/32/4839_2.png) [@Cat\_Whisperer](https://boards.straightdope.com/u/Cat_Whisperer)\ **Post date:** [September 23, 2013, 5:56am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/43 "2013-09-23T05:56:59Z")
> [@DrDeth](#): > > What’s interesting, we were handing out some reflectors and stuff to some bicyclists (San Jose Bike Party, kinda like Critical Mass but less assholes\*), and there were a group of them with fixies, they were all wearing black on black with black highlights, nary a one had any lights or reflectors. One said “You can’t hit what you can’t see.”\* and he was serious. \*\ “Well, not on purpose.” ---
**Author:** ![Seanette](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/seanette/32/9139_2.png) [@Seanette](https://boards.straightdope.com/u/Seanette)\ **Post date:** [September 23, 2013, 6:21am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/44 "2013-09-23T06:21:59Z")
> [@kaylasdad99](#): > > I turn on my headlights when I start the car. I don’t have daytime running lights, though. It’s just something I do. My husband does that. I don’t, because I’m entirely too good at failing to turn them off when parking during the day. At night, I can notice they’re still on, but seem to blip right past that during the day. I totally agree with the OP. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [September 23, 2013, 6:58am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/45 "2013-09-23T06:58:37Z")
> [@Rick](#): > > The tires were spinning at 120MPH but since there was essentially no friction between the tires and the road, courtesy of the standing water, the car was going maybe 3 MPH. > the person that wrote this (and everyone that has re-published it) think that the speed of the tires = the speed of the car. In reduced traction conditions, this is not a true statement. > That is my objection to this piece of glurge. > It also ignores the safeties built into modern cruise controls. > Here is an [excellent discussion of hydroplaning](http://auto.howstuffworks.com/car-driving-safety/accidents-hazardous-conditions/hydroplaning.htm) > [Here is the standard (wrong) letter](http://urbanlegends.about.com/library/bl-cruisecontrol.htm) about this Wouldn’t the issue be what happens when your tyres, that have spun up due to low traction, gain traction again? If they’ve spun up enough they will momentarily launch you forwards until you (or the cruise control) corrects it. It does point to an inherent flaw in cruise control, that you don’t have direct control over the car and there is a slight delay while you get your foot on the brake whereas if you had your foot on the accelerator you start the slowing down process the moment you remove your foot. I would assume though that cruise control would have some system of detecting skidding by monitoring all of the wheel speeds. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [September 23, 2013, 7:14am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/46 "2013-09-23T07:14:04Z")
> [@Rick](#): > > Here is what really happened: > So back when I was 18 or so, I was in an underground parking garage that had a very smooth concrete surface and had flooded to about 1" deep from rain. I goosed my parents Big Dodge V8 and broke the tires loose. My buddy was laughing his ass off and told me to stop so he could get a picture. I let him out and floored it. Engine revved up, tires broke loose, trans shifted and away we went at a walking pace. My buddy was walking next to the car talking to me as the speedo registered 120 MPH. The tires were spinning at 120MPH but since there was essentially no friction between the tires and the road, courtesy of the standing water, the car was going maybe 3 MPH. > the person that wrote this (and everyone that has re-published it) think that the speed of the tires = the speed of the car. In reduced traction conditions, this is not a true statement. > That is my objection to this piece of glurge. > It also ignores the safeties built into modern cruise controls. > Here is an [excellent discussion of hydroplaning](http://auto.howstuffworks.com/car-driving-safety/accidents-hazardous-conditions/hydroplaning.htm) > [Here is the standard (wrong) letter](http://urbanlegends.about.com/library/bl-cruisecontrol.htm) about this What would have happened if you hit a dry spot there, though? You would have suddenly accelerated and flown into the wall. That’s the basic problem with cruise control and hydroplaning-- you hit the puddle which slows you down fast and so the CC responds by giving it full throttle. But then the wheels break traction so there’s no resistance and so the wheels spin up past what the CC is set for. Then, a second later, you’re out of the puddle, the wheels grab traction while spinning way past what the CC is set for and… off you go! This won’t happen on a newer car because the CC will already back off as soon as the tires start spinning, but older CC systems were far less responsive and you could get a fair amount of speed up before the slop in the system caught up. Playing around in a snowy parking lot with an old Taurus I had, I could pretty consistently get it to do a thing where I would set the CC to 25 (as low as it went), it would spin the wheels, back off, and then overcompensate the instant it caught traction again, with the net effect of a feedback cycle that caused the car to continually speed up past where the CC was set. It’s definitely not the wild out of control acceleration suggested by the e-mail, but considering how long that stupid thing has been floating around the inbox-o-sphere I wouldn’t be surprised if it was talking about an older Towncar with a CC system that could do some genuinely scary stuff on wet roads. ---
**Author:** ![Morgyn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/morgyn/32/3041_2.png) [@Morgyn](https://boards.straightdope.com/u/Morgyn)\ **Post date:** [September 23, 2013, 4:51pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/47 "2013-09-23T16:51:32Z")
> [@HMS\_Irruncible](#): > > And while I’m ranting, stop fucking driving with your hazard flashers on. If you’re that hazardous, get the fuck off the fucking road and call a fucking tow truck, don’t drive on the interstate all “Ooh, I’ve got a problem, best stay away from me.” They may have been on to warn you that the driver was going 10 or more mph less than the posted speed limit. I believe that’s a fairly standard law. You often see the big trucks with their hazards on when they’re climbing a steep grade. (Oh, yeah, and TURN ON YOUR FUCKING LIGHTS, YOU DICKHEADS. I CAN’T SEE YOU!) ---
**Author:** ![CanvasShoes](https://avatars.discourse-cdn.com/v4/letter/c/74df32/32.png) [@CanvasShoes](https://boards.straightdope.com/u/CanvasShoes)\ **Post date:** [September 23, 2013, 5:30pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/48 "2013-09-23T17:30:59Z")
When I moved to WA three years ago, from AK (the second highest COL in the US), my car insurance went UP by about 40 bucks. The insurance agent told me it was because WA has the worst drivers and highest percentage of uninsured drivers in the US. I remember being irritated at this very thing. Not so much at dusk and dawn, since I commuted to work by Light Rail, but more when it was raining. It’s dark, and visibility is low and idiots are driving around in “the Grey” without headlights. I’m fully on-board with this pitting. ---
**Author:** ![Cat\_Whisperer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cat_whisperer/32/4839_2.png) [@Cat\_Whisperer](https://boards.straightdope.com/u/Cat_Whisperer)\ **Post date:** [September 23, 2013, 5:47pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/49 "2013-09-23T17:47:52Z")
> [@Seanette](#): > > My husband does that. I don’t, because I’m entirely too good at failing to turn them off when parking during the day. At night, I can notice they’re still on, but seem to blip right past that during the day. > > I totally agree with the OP. Doesn’t your car beep at you if you open the door with the lights still on? Mine does, which is one of the reasons I always turn mine on. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [September 23, 2013, 7:06pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/50 "2013-09-23T19:06:24Z")
I haven’t really noticed the “too cool/oblivious to turn on my headlights” thing. What I _would_ appreciate is that if you are riding a bike at night in or just off the traffic lane in a totally unlit area, at least have some sort of rear reflector and preferably wear light-colored clothing. This also applies to pedestrians walking in or just off the edge of the road. I am not psychic and you are not immune to the forces of physics. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [September 23, 2013, 7:29pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/51 "2013-09-23T19:29:10Z")
> [@Rick](#): > > Get all four hydroplaning and things can get interesting. First time it happened to me car went from straight ahead to 90 degrees off the direction of travel in nothing flat. That was fun. I’ve seen a big ol’ sedan hydroplane down [a sloped parking lot, jump a curb, and come to rest between some trees](https://maps.google.com/maps?q=columbia+pike+at+wakefield+street,+arlington,+va&hl=en&ll=38.85738,-77.106171&spn=0.006567,0.009356&sll=38.857280,-77.106490&layer=c&cbp=13,65.13,,0,24.83&cbll=38.857424,-77.106431&hnear=Columbia+Pike+%26+S+Wakefield+St,+Arlington,+Virginia+22204&t=h&z=17&panoid=DaVKfxB1j5fxUXQDXSeU2g). County PD happened to be working a three-vehicle collision at the top of the hill so it shouldn’t have taken long to render aid. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [September 23, 2013, 7:36pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/52 "2013-09-23T19:36:24Z")
> [@John\_Mace](#): > > I got up early the morning and made the drive down to Carmel. There’s a section of Hwy 1 that is only two lanes as it goes through Moss Landing (one lane in each direction). It’s a designated “daylight headlights” section, although that’s not enforced by law. Ditto a stretch of 152/154 from Gilroy to I5. I thought it was a requirement, though I don’t know if it is enforced. Most cars have their lights on, though. What bugs me is this. California has a law requiring lights on during the rain, defined as enough rain to use your full wipers, not just intermittent. At least a third of the cars don’t bother. Even in really heavy rain. ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [September 23, 2013, 8:43pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/53 "2013-09-23T20:43:52Z")
> [@runner pat](#): > > Why? Everything reacts badly to hydroplaning. 😃 Except, of course…hydroplanes ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [September 23, 2013, 9:13pm UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/54 "2013-09-23T21:13:43Z")
> [@RaftPeople](#): > > Except, of course…hydroplanes If a hydroplane was on a watermill… ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [September 24, 2013, 12:44am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/55 "2013-09-24T00:44:59Z")
> [@Lute Skywatcher](#): > > If a hydroplane was on a watermill… …would it float off? ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [September 24, 2013, 2:32am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/56 "2013-09-24T02:32:05Z")
> [@CanvasShoes](#): > > I remember being irritated at this very thing. Not so much at dusk and dawn, since I commuted to work by Light Rail, but more when it was raining. It’s dark, and visibility is low and idiots are driving around in “the Grey” without headlights. I’m fully on-board with this pitting. > [@Voyager](#): > > What bugs me is this. California has a law requiring lights on during the rain, defined as enough rain to use your full wipers, not just intermittent. At least a third of the cars don’t bother. Even in really heavy rain. Here’s a photo I took last year during Wenatchee’s annual forest/brush fire, to show the smoke filling our valley: [http://mister-rik.com/hosted/smoke.jpg](http://mister-rik.com/hosted/smoke.jpg) But ignore the smoke and look at the vehicles. This is just a random selection of the vehicles that happened to be passing by when I snapped the photo. What do you see? They’re all white or silver (heck, _my_ car is white). Now picture all of these idiots driving down this street in December. With snow on the ground and on the road. And heavy snow falling. And most of them don’t have their headlights on, because, hey, it’s daytime. The photo was taken from my apartment’s front door; I have to parallel park on that street. So try to imagine the difficulty I have pulling into traffic under the conditions I described. More than once I’ve said, “Fuck this”, turned off my car, and just walked (work was only six blocks away). ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [September 24, 2013, 3:20am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/57 "2013-09-24T03:20:55Z")
Hey, at least you can walk to “Jack in the Box” for supper. ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [September 24, 2013, 3:44am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/58 "2013-09-24T03:44:26Z")
> [@Leaffan](#): > > Hey, at least you can walk to “Jack in the Box” for supper. And I have done so many times. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [September 24, 2013, 4:00am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/59 "2013-09-24T04:00:16Z")
> [@Richard\_Pearse](#): > > Wouldn’t the issue be what happens when your tyres, that have spun up due to low traction, gain traction again? If they’ve spun up enough they will momentarily launch you forwards until you (or the cruise control) corrects it. It does point to an inherent flaw in cruise control, that you don’t have direct control over the car and there is a slight delay while you get your foot on the brake whereas if you had your foot on the accelerator you start the slowing down process the moment you remove your foot. I would assume though that cruise control would have some system of detecting skidding by monitoring all of the wheel speeds. Well in a word, no. Want proof? Here you [go](http://www.youtube.com/watch?v=sOGhuhC4AF0) > [@GreasyJack](#): > > What would have happened if you hit a dry spot there, though? You would have suddenly accelerated and flown into the wall. That’s the basic problem with cruise control and hydroplaning-- you hit the puddle which slows you down fast and so the CC responds by giving it full throttle. But then the wheels break traction so there’s no resistance and so the wheels spin up past what the CC is set for. Then, a second later, you’re out of the puddle, the wheels grab traction while spinning way past what the CC is set for and… off you go! This won’t happen on a newer car because the CC will already back off as soon as the tires start spinning, but older CC systems were far less responsive and you could get a fair amount of speed up before the slop in the system caught up. > > Playing around in a snowy parking lot with an old Taurus I had, I could pretty consistently get it to do a thing where I would set the CC to 25 (as low as it went), it would spin the wheels, back off, and then overcompensate the instant it caught traction again, with the net effect of a feedback cycle that caused the car to continually speed up past where the CC was set. It’s definitely not the wild out of control acceleration suggested by the e-mail, but considering how long that stupid thing has been floating around the inbox-o-sphere I wouldn’t be surprised if it was talking about an older Towncar with a CC system that could do some genuinely scary stuff on wet roads. First off in all of my years of driving, I don’t think I have ever gone from hydroplaning, or potential hydroplaning to flat dry and perfectly dry with great traction in the blink of an eye. Have you? Next those cars you are describing have very stone age CC units. A modern CC on a modern car has several safety disconnects that prevent this from happening. Also go back and read the original email, they state the wheels were off the ground, but the car accelerated. That is flat impossible unless you are using a jet engine in your car. NO traction = no acceleration. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [September 24, 2013, 5:33am UTC](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368/60 "2013-09-24T05:33:35Z")
> [@Rick](#): > > Well in a word, no. Want proof? Here you [go](http://www.youtube.com/watch?v=sOGhuhC4AF0) I watched the Mythbusters episode on this (driving a car into the back of a moving truck) and for the life of me I cannot figure out the physics involved. Why the car doesn’t rocket to the front of the truck mystifies me. If my drive wheels are making my car travel at, say, 60 MPH on the highway, and I’m moving onto a truck traveling at 55 MPH, I would expect that once the drive wheels touched the moving truck I would be moving at 60 MPH relative to the truck, or 115 MPH total. There’s something about inertia in the Mythbusters explanation, but I don’t get it. [Previous page](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368.md?page=2) [Next page](https://boards.straightdope.com/t/i-pit-those-who-dont-know-when-the-fuck-to-turn-on-their-headlights/669368.md?page=4)