Half a croissant, on a plate, with a sign in front of it saying '50c'
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Alternate day/night speed limits

Different traffic conditions call for different speed limits
  [vote for,

One thing I've noticed across the country (in the U.S. at least) is that there is considerably less traffic at night than during the day. I drive 30 miles to work at 4 am every morning, and there is *no* other traffic on the road except truckers, and not many of them, either. The speed limit, for a long part of the drive, is 60 mph. On flat, even, wide, open road. The speed limit is the same if there is no traffic as it is if there is bumper-to-bumper traffic.

I think there should be speed limit signs with a higher posted speed for late-night driving, as well as the time they become effective (say, 11 pm, for instance). The signs should be another color (red is good) to easily distinguish between the day/night signs so drivers can't plead confusion.

So basically, the sign would read like this (but in red with white letters):

11 PM -

7 AM

75 mph

There would be a large sign at each on-ramp saying something like "OBEY RED SIGNS ONLY AT NIGHT". I realize that wording might not necessarily be the best, but you get the drift...

(this was my wife's idea, actually)

21 Quest, Oct 21 2006

Nighttime speed limit http://en.wikipedia.../Image:100_1816.JPG
Lower at night because of likely impact on cattle [lurch, Oct 21 2006]


       Or the signs could be digital and be Programed to change Readings from 11:00 PM-7:00AM
Troxin_420, Oct 21 2006

       Yes, [Troxin]'s mod would be more user friendly.
daseva, Oct 21 2006

       [Troxin]'s mod would be more expensive, too.
21 Quest, Oct 21 2006

       I'm with you on this one [21]. The UK is exactly the same (as are most countries probably). I see no reason to drive at a severely resticted speed if you're the only one on the road. More specific to me, there are ongoing motorway roadworks which have a 40mph limit, even at night, when the motorway is empty. I proffer you a large bun, with the topping/filling of your choice.
jtp, Oct 21 2006

       In the US, these used to be a black sign with white lettering on the same post as the white sign with black lettering daylight speed limit. However, contrary to your intent, the nighttime speed was lower than daytime speed because of that visibility thing.
lurch, Oct 21 2006

       Well that makes sense, in residential areas, lurch. Not on interstates, where the speed limit is already 60 +.
21 Quest, Oct 21 2006

       I've seen these black and white signs in Arizona within the last two years. Since they are already recognized, why not just use this scheme on freeways as suggested? Certainly nothing about the paint, the metal, or the size of the sign would stop us from making ones where the nighttime limit is higher.

       Of course, I believe that rather than giving a time, the nighttime limit says "after dark," which may or may not cause some confusion around twilight hours.
ye_river_xiv, Oct 22 2006

       I think I've seen something like that before.
apocalyps956, Oct 22 2006

       Fraid I have to disagree with you [21 Quest]. Speed limits aren't for convenience (and expedience) they are supposed to be for safety.

       I'd love to drive faster than the speed limit, honestly, but just because a road is quieter at night time doesn't mean that the limit should be relaxed. I've done my fair share of night-motorway driving and when it is quiet it is so tempting to put the foot down and justify it to one's elf.

       But visibility is reduced, so therefore you aren't as likely to spot something on the road. If anything, the speed limit should be reduced.

       <aside> The major roads in France (probably Europe) have different speed limits for wet/dry conditions.</aside>
Jinbish, Oct 22 2006

       //spot something on the road//

       Like what? Pedestrians or cyclists who aren't even legally allowed on interstates? Besides, my brights provide more than adequate illumination, not to mention that a good portion of the interstate here is lit with streetlights. I've actually found that road debris is easier to spot at night because my headlights iluminate it from the angle from which I'm seeing it; basically, my headlights hitting it from the side make it glow like a beacon. This often is not the case in daytime driving, where, if you're driving into the sun, or if it's just a particularly bright day, you have a major reduction in visibilty caused by glare.
21 Quest, Oct 22 2006

       //spot something on the road//

       Like anything. Perhaps even spotting the road in the first place (sharp bends etc.)

       I don't think that driving at night is any safer than during the day. Ok - there is possibly glare from the sun, but there is also glare from other motorists headlights. If headlights were so good, we wouldn't have cats-eyes. On saying that, I actually prefer drving long distance at night.

       However, night time isn't actually the main point here - it's the ability to go faster on a quiet road. It just so happens that the interstate is quieter at night.

       The speed limit should reflect the driving conditions and the location of the road. A couple of roads I can think of change their speed limit during times of possible congestion (M25 outside of London).

       If the road is busy at particular times then go ahead and reduce the speed limit, but you don't just increase a speed limit because it's night time. The same argument will hold for a big, quiet road during the day time.

       The solution is to have as high a speed limit as deemed safe and the reduce that in certain circumstances (rush hour).
Jinbish, Oct 22 2006

       The New Jersey Turnpike has had these "digital" signs for the better part of 20 years now. These signs can be changed by the authorities from a remote location based on weather or road conditions.

       I too have seen the DAY/NIGHT speed limit signs posted alongside the interstate highway in Washington, DC. It too has the slower speed at night and faster speed during the day. Up until recently, though, nobody had ever obeyed the speed limit and none of the police officers have ever enforced it. It was all too common to go 85 MPH in a 50 MPH zone only to be tailgated by a cop who is trying to pass you.

       Anyhow, I think that cops that are working the graveyard shift are seldom set up for speed traps. Many of them are resolving domestic disputes or robberies. And those who are set up to catch speeders in the middle of the night are probably in their car asleep. So after 11PM, SPEED ON my friend. Speed on!
Jscotty, Oct 22 2006

       Quest I love it, if used in the right area this idea is great. One slight problem could be the regulation of interpitation of time representation. What I mean is how do you tell a cop its night time? Simply posting times wouldnt work due to daylight savings or simply the altering "time it gets dark" of every passing day.
Chefboyrbored, Oct 23 2006

       When the time changes, change the signs, if necessary. Here, it's always dark at 11 PM, no matter what time of year. The morning time might need change, but a large refrigerator magnet over the 7 AM part with a different time could do the trick.
21 Quest, Oct 23 2006

       //spot something on the road//

       //Like what? Pedestrians or cyclists who aren't even legally allowed on interstates?//

       Like deer, cows, horses. Sleeping drivers, stalled vehicles, construction. The list is endless. Driving at night is way more dangerous than daytime driving, a fact not lost on the highway departments that have done the studies and decided it's a good idea to lower speeds at night and posted them thusly.
Noexit, Oct 23 2006

       Oh come on, now! I've only hit one cow with my mother's minivan...

       (note: that was a joke, not an actual argument)
21 Quest, Oct 23 2006

       Is it considered animal cruelty if the cow dies by any other means other than the slaughterhouse?
Jscotty, Oct 23 2006

       If it was hit by a lorry transporting porridge, it might be animal gruelty.
imaginality, Oct 23 2006

       They have these in Germany, too. Many sections of Autobahn have differing day-time and night-time limits. I think it's more to do with noise reduction where the road passes near residential areas, though.

       As quite a few people have given examples of these signs existing, can we say - baked and widely known to exist?
squeak, Oct 24 2006

       Actually, it walked away. Farmer had to pay for damages to the van because of a nice little ordinance called "livestock at large".
21 Quest, Oct 24 2006

       Squeak, so far I have seen many examples of speed limits being lowered at night, but none of speed increasing at night. While I realize there may well be a good reason for this, rendering this idea possibly invalid, this idea is not baked as far as I can tell from the evidence displayed thus far.
21 Quest, Oct 24 2006

       //If it was hit by a lorry transporting porridge, it might be animal gruelty.// -[imaginality]

       You actually hurt me, I mean physically hurt me on that pun. I hope you're proud of yourself.
NotTheSharpestSpoon, Oct 24 2006

       Raising speed limits at night is not baked. However, the title of the idea, "Alternate day/night speed limits", and the subtitle, "Different traffic conditions call for different speed limits", seem to indicate an idea about day/night variance of speed limits, which is not even uncommon.

       Time of onset is, in most jurisdictions, regulated by the same rules governing use of headlights, i.e., 30 min after local sunset to 30 min before local sunrise, or similar.
lurch, Oct 25 2006

       Just as you should drive according to the conditions, so the speed limit should be determined by the conditions; the trouble with this idea is that night-time does not necessarily imply that a higher limit is appropriate, and I believe (confirmation, please) that US interstates don't have complete coverage in respect of CCTV, sign gantries, etc, to enable real-time amendments.

<aside> Has anyone else experienced the 'active traffic management' system on the M42 motorway in UK? It's intended to improve traffic flow during busy periods by lowering the speed limit in an apparently arbitrary and random manner to 60, 50 or even 40. The current limit is posted on overhead signs. It fails to work in the most spectacular fashion.</aside>
angel, Oct 26 2006

       [NTSS], I apologise - I admit inflicting that pun on you was oatally out of order.
imaginality, Oct 26 2006


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