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Speed humps are interesting because they're seldom designed to be SUPER punishing. They might be less punishing as a compromise to drivers comfort or to buses. A 4WD or off road designed vehicle, like a dirt bike, can easily go over speed humps at 40-50km/h with minimal discomfort. I've seen speeds of up to 70km/h recorded on a short stretch of narrow road in the 50m length between two speed humps. The point is, they slow the average traffic speed, as do chicanes. The average speed is also what correlates better with crash rate. They don't stop people who want to use the street for racing if they're determined: they'll just go to the next street over that doesn't have them. What's more is that they don't stop people braking/accelerating heavily between them: frankly, I don't see them as a decent solution to the 'problem' of street racers. Probably the best solution might be too just give them a racecourse of their own and legitimise it but that's not going to be ok with boomers. I expect that crash statistics are fairly nonexistent around them, but probably because of underreporting because most nose to tail crashes aren't going to cause death or serious injury. Insurance companies and the like might have statistics but who knows how robust their investigations into crashes will be. A well designed one would usually be pretty clearly visible to drivers so they'd not be caught off guard by it. As far as slapping on speed limit signs go, that doesn't always work but can make a small difference in some situations, like when the street is already narrowed. But it's very small, and actual street design plays a much bigger part, and won't really work if there's no thought put into it
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Apr 29, 2021 02:35
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Lobsterpillar posted:Speed humps are interesting because they're seldom designed to be SUPER punishing. They might be less punishing as a compromise to drivers comfort or to buses. A 4WD or off road designed vehicle, like a dirt bike, can easily go over speed humps at 40-50km/h with minimal discomfort. I've seen speeds of up to 70km/h recorded on a short stretch of narrow road in the 50m length between two speed humps. It's emergency services that typically object to super punishing speed bump designs. It slows down response time and can damage ambulances, fire trucks and whatnot. Those types of vehicles don't have the same acceleration that personal cars typically have, so you have to think about who you're really calming there. You also want to avoid speed bumps or humps on any kind of road frequently traveled by freight trucks. All you're doing is bouncing goods around in the trailer, plus they'll get ruts worn into them pretty quickly unless constructed of reinforced concrete. Roundabouts, neckdowns, sharper curves, road diets, narrowed lanes, mixed-use paths instead of bike lanes, etc. are usually preferred to speed bumps if you can afford the budget. Varance fucked around with this message at 03:18 on Apr 29, 2021 |
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Apr 29, 2021 03:04
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Why not just use speed cameras? They don’t impact emergency vehicles, so they seem like a great option to me. Not as good as designing the road to encourage slower driving, but still better than speed bumps. Are they more expensive than they look?
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Apr 29, 2021 04:26
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nrook posted:Why not just use speed cameras? They don’t impact emergency vehicles, so they seem like a great option to me. Not as good as designing the road to encourage slower driving, but still better than speed bumps. In the Netherlands there was at least one court cases where all fines from a certain speed camera were scrapped entirely because the speed camera was placed on a road that only had a max speed sign slapped onto it and had no traffic calming measures whatsoever. To summarize the ruling in my own words, the court considered it worse than a bandaid - they considered it a way by the city council to cheat people out of their money by putting the cam on a road where the road design itself (fast speeds) didn't match the much lower max speed sign.
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Apr 29, 2021 07:36
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nrook posted:Why not just use speed cameras? They don’t impact emergency vehicles, so they seem like a great option to me. Not as good as designing the road to encourage slower driving, but still better than speed bumps. Carbon dioxide posted:In the Netherlands there was at least one court cases where all fines from a certain speed camera were scrapped entirely because the speed camera was placed on a road that only had a max speed sign slapped onto it and had no traffic calming measures whatsoever. To summarize the ruling in my own words, the court considered it worse than a bandaid - they considered it a way by the city council to cheat people out of their money by putting the cam on a road where the road design itself (fast speeds) didn't match the much lower max speed sign.
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Apr 29, 2021 15:56
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wolrah posted:Every road has a natural speed, and if the limit is set lower than that it is wrong. Stricter enforcement of bad speed limits is never the right answer. If the natural speed of a road is higher than you want, you must change the road. If you need to design road so that a huge amount of truck traffic can get through it during rush hour how will you stop sports car running though it at 200km/h during night? Just yesterday I drove through a beachfront street that definitely employs this thinking, all cars crawl along and you really need to worry about hitting the parked cars with oncoming traffic. But if a pair of Hummers happen to meet at the wrong spot everyone will have wonderful time backing out of the street. Frankly, I wish for a gapless speed enforcement so forget about all the risk-reward calculation with speeding, just keep a realtime fine counter running. If I want to pass a car I can estimate in advance how much it would cost and if it would be worth it.
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Apr 29, 2021 22:14
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I do realize that speed cameras are considered unacceptable in many locations for ideological reasons. I was just wondering if there were more practical concerns as to their use.
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Apr 30, 2021 03:02
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wolrah posted:This is wonderful and should be the standard response by any reasonable court. If it's applied consistently, how is it "cheating" anyone? If anything, putting in average speed cameras on all roads (or installing them in the cars themselves if that becomes feasible) so the default expectation for drivers is that violating speed limits results in a fine would work better than any traffic calming measure. But at the same time, speed limits should make sense. A road that's built in a way that allows 45mph traffic can still be set to 15mph during certain hours if it goes by a school. And a freeway that can handle 100mph traffic shouldn't be limited to 55mph in the middle of the night. Overengineer the roads, but set speed limit to safe levels and enforce them consistently. And as an aside the fines should be a percentage of income/wealth though to keep things equitable.
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Apr 30, 2021 03:10
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nrook posted:I do realize that speed cameras are considered unacceptable in many locations for ideological reasons. I was just wondering if there were more practical concerns as to their use. You have to have almost continuous coverage for them to work as a safety measure (see UK's high-speed freeway system) and change behavior. Otherwise you tend to just get a local effect where locals/commuters slam on their brakes at the speed camera, then speed up again once they're past. Random tourists will tend to just get caught by the camera. Someone doing 80mph in the city doesn't particularly worry about the possibility of a fine. The abrupt changes in speed are not great for minor safety issues. If it's more than a 2-lane 2-way road, you also get abrupt lane changes when someone slows to 25mph in a 30mph zone. Some people know the camera activates at 42mph, so you have an instantaneous adjustment where the left lane of cars has a bunch of people cooperating going 40mph, then one person slows down to 25, and now everyone is jockeying to figure out their new position. There was a setup that caused this issue on a 4-lane divided highway near me signed at 35mph; they took the cameras out after a few years and too many accidents.
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Apr 30, 2021 04:03
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Also note that it's incredibly important that if you do design a road for high speeds, you cannot put driveways, building entrances and lots of intersections on that road. That'll cause a lot of brake slamming and delays, and an unsafe situation for everyone. Besides, if you design roads to be separate from access streets, you'll get trucks mostly on roads and the only trucks you see on the streets will be those that actually need to deliver there, so Saukkis posted:If you need to design road so that a huge amount of truck traffic can get through it during rush hour how will you stop sports car running though it at 200km/h during night? while it doesn't solve this problem, at least you don't get the sports car racing through your neighbourhood where the kids are playing on the lawn. See the video about stroads I posted on the previous page for more info.
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Apr 30, 2021 07:25
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Our local road crew is as good at applying stickers as I am.
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Apr 30, 2021 12:54
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Saukkis posted:If you need to design road so that a huge amount of truck traffic can get through it during rush hour how will you stop sports car running though it at 200km/h during night? Even in Germany on the derestricted sections of Autobahn the average speed is a bit under 90 MPH. The kinds of straight, flat, nothing changing for miles rural interstate highways we have in the US midwest can (and often do in my experience) support traffic flowing around that same speed just fine. quote:Just yesterday I drove through a beachfront street that definitely employs this thinking, all cars crawl along and you really need to worry about hitting the parked cars with oncoming traffic. But if a pair of Hummers happen to meet at the wrong spot everyone will have wonderful time backing out of the street. Anyways, there are all kinds of traffic calming measures available, obviously you use the ones that are best suited for the needs of the area. quote:Frankly, I wish for a gapless speed enforcement so forget about all the risk-reward calculation with speeding, just keep a realtime fine counter running. If I want to pass a car I can estimate in advance how much it would cost and if it would be worth it. Aside from the insane privacy issues involved in any way that could work, it'd need to be scaled by income or it would effectively be a free pass to those rich enough to not care about the fine. AreWeDrunkYet posted:If it's applied consistently, how is it "cheating" anyone? If anything, putting in average speed cameras on all roads (or installing them in the cars themselves if that becomes feasible) so the default expectation for drivers is that violating speed limits results in a fine would work better than any traffic calming measure. quote:But at the same time, speed limits should make sense. A road that's built in a way that allows 45mph traffic can still be set to 15mph during certain hours if it goes by a school. And a freeway that can handle 100mph traffic shouldn't be limited to 55mph in the middle of the night. Overengineer the roads, but set speed limit to safe levels and enforce them consistently. If the school is impossibly badly located where such a widely varying speed limit change is legitimately the best option, maybe some kind of movable barrier system would be the right answer. It's really hard to shift the natural speed of a road between 45 and 15 without extreme measures. Carbon dioxide's posts are solid too. Especially that stroad video.
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Apr 30, 2021 18:22
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More than 30,000 people die every year in the United States in motor vehicle accidents. There are certainly ideals worth dying for in this world. But I'm not convinced the 85% rule is one of them.
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Apr 30, 2021 19:18
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Devor posted:You have to have almost continuous coverage for them to work as a safety measure (see UK's high-speed freeway system) and change behavior. This makes sense, thanks. If there are a few places with speed cameras, you're going to see people suddenly changing speed in order to avoid getting caught.
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Apr 30, 2021 19:20
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nrook posted:More than 30,000 people die every year in the United States in motor vehicle accidents. What do you mean by the 85% rule being an ideal? The idea is that a good speed limit to set is the 85th percentile speed. The only research that I've read on changing the speed limit to reduce accidents, is variations on this: quote:Lowering speed limits below the 50th percentile does not reduce accidents, but does significantly increase driver violations of the speed limit. Conversely, raising the posted speed limits did not increase speeds or accidents. https://www.ibiblio.org/rdu/sl-irrel.html
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Apr 30, 2021 19:44
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nrook posted:More than 30,000 people die every year in the United States in motor vehicle accidents. The argument is that roads are safer with the 85% rule than without. Laws should be the last line to discourage an action, not the first. An analogy would be how music piracy went down less from the RIAA suing people than it did from people having more convenient legal options.
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Apr 30, 2021 19:44
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If pirating music universally led to a fine a day later, it would definitely have an effect on piracy! Speedy enforcement is great for deterring lawbreaking. I would be against such a policy, of course, but that’s because nobody dies when I download a Coldplay album. I don’t work in this academic field, but just from some brief searching it’s not hard to find articles arguing that speed cameras decrease speeding and decrease collisions. Here’s one example (though with the big caveat that all the cameras they mentioned followed the 85% rule—the authors say that isn’t very important, but still.) The CDC lists a number of studies. The idea that a speed limit below the 85th percentile is unjust, rather than merely ineffective, is what I meant when I described it as an ideological position.
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Apr 30, 2021 20:33
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The problem with the 85% rule is that it relies on people being rational actors, being skilled enough to actually safely judge what is a safe speed and that all vehicles are the same size. The immediate area I live in the roads are very narrow with some tight bends but people still drive too quickly and have to take evasive action when meeting oncoming traffic. This gets even worse with the large delivery lorries or buses when there is literally not enough space for them to pass each other without going onto the footpath. What works for my Panda with a decent driver doesn't work with a big transit from Amazon who is paid by the delivery. Scotland past Edinburgh and Glasgow has average speed cameras on all the main duel carriageways and they flow better than the ones in England and everyone is going at the safe speed for there vehicle. I just can't see a way you can design a road for an HGV that limits its speed while still being safe for the HGV and other road users.
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Apr 30, 2021 22:40
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nrook posted:If pirating music universally led to a fine a day later, it would definitely have an effect on piracy! Speedy enforcement is great for deterring lawbreaking. I would be against such a policy, of course, but that’s because nobody dies when I download a Coldplay album. See, the quote I was responding to sounded like you were arguing that people just wanted faster speed limits and safety be damned. Most people arguing for 85th percentile are of the opinion that 1)it is safer to have more people driving the same speed than some people speeding and some doing the limit and 2)police/cameras can't catch everyone so slowing road traffic through road features are more effective and free police up to go after the lower number of people still speeding. Now, people like the poster above me can argue the effectiveness of 85% speed limits, but most of the people arguing for it are, like you, looking for safer roads.
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May 1, 2021 00:10
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Foxtrot_13 posted:The immediate area I live in the roads are very narrow with some tight bends but people still drive too quickly and have to take evasive action when meeting oncoming traffic. This gets even worse with the large delivery lorries or buses when there is literally not enough space for them to pass each other without going onto the footpath. If you're talking about rinky dink 2-lane roads, then the 85% speed stuff ~does not apply~. For tiny little roads, it's all about radius of curves, lane widths, pavement markings, and sight distance. People talking about 85% speed, and speed differentials, are talking about highways (carriageways?) where someone going slow causes people to weave around them. On a narrow 2-lane road, someone else going slow just makes everyone behind them go slow too. Lowering the speed limit (without other changes) would not cause most people to drive slower, and wouldn't stop a crazy delivery guy from scaring the poo poo out of you. If crazy Amazon drivers are causing accidents, your limited recourse is: 1. Complain to Amazon (ha, good luck) 2. Complain to whoever maintains/improves your roads about adding fog lines / centerline striping / rumblestrips (maybe worthwhile?) 3. Take different roads (if possible)
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May 1, 2021 02:07
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85% is misused in the US. Here the idea seems to build the road and then figure out the speed from how people drive on it. Instead you should designed the road so the 85% speed is the speed you want. Like the residential street in front of my house is 50 feet wide. It allows street parking, but it isn't packed. People don't do 25 here. Narrowing it even 10 feet would have a huge impact.
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May 1, 2021 22:38
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Lowest speeds I've seen are on dinky little narrow roads barely wide enough for cars to park on one side which have no attractiveness as a thoroughfare. And even then, some residents of the street say there's a problem with speed. Turns out one of the residents of the street owns a fast car with no muffler.
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May 1, 2021 23:02
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Is there a downside to incrementally closing more roads to cars to encourage other forms of traffic like New York and Oakland have been trying? It seems like a remarkably simple idea to deal with excess vehicular traffic, and a lot cheaper than engineering roads for traffic calming measures. And as a bonus if it results in more traffic on the remaining streets that allow cars, that's just more incentive for people to use alternative transportation.
AreWeDrunkYet fucked around with this message at 23:34 on May 1, 2021 |
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May 1, 2021 23:24
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AreWeDrunkYet posted:Is there a downside to incrementally closing more roads to cars to encourage other forms of traffic like New York and Oakland have been trying? It seems like a remarkably simple idea to deal with excess vehicular traffic, and a lot cheaper than engineering roads for traffic calming measures. And as a bonus if it results in more traffic on the remaining streets that allow cars, that's just more incentive for people to us alternative transportation. Mostly the very loud petulant meltdowns of car people writing thousands of letters to the editor every day about how their house will burn down because the fire trucks won't be able to reach them in time due to all the bike lanes and crosswalks.
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May 1, 2021 23:28
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Baronjutter posted:Mostly the very loud petulant meltdowns of car people writing thousands of letters to the editor every day about how their house will burn down because the fire trucks won't be able to reach them in time due to all the bike lanes and crosswalks. What if the firemen forget how to use GPS!?!?!!!
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May 1, 2021 23:41
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AreWeDrunkYet posted:Is there a downside to incrementally closing more roads to cars to encourage other forms of traffic like New York and Oakland have been trying? It seems like a remarkably simple idea to deal with excess vehicular traffic, and a lot cheaper than engineering roads for traffic calming measures. And as a bonus if it results in more traffic on the remaining streets that allow cars, that's just more incentive for people to use alternative transportation.
I think, similar to roundabouts, once there are more successful examples of it working the idea will start to gain more traction. Nobody wants to spend a bunch of money trying something only to have to redo everything later.
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May 1, 2021 23:45
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AreWeDrunkYet posted:Is there a downside to incrementally closing more roads to cars to encourage other forms of traffic like New York and Oakland have been trying? It seems like a remarkably simple idea to deal with excess vehicular traffic, and a lot cheaper than engineering roads for traffic calming measures. And as a bonus if it results in more traffic on the remaining streets that allow cars, that's just more incentive for people to us alternative transportation. Mainly NIMBYism, I think. You have to do it systematically though, considering all the road network as a whole. Because theoretically the results could be awful if the sole streets not so converted, which become arterial, aren't set up for it and connected to other high-speed roads properly.
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May 2, 2021 00:21
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 https://twitter.com/myfdot_sefl/status/1390329280991834118
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May 6, 2021 20:35
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gently caress I just came to post that. That’s amazing.
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May 6, 2021 21:15
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nm posted:85% is misused in the US. Here the idea seems to build the road and then figure out the speed from how people drive on it. And of course there's also the people who want a wide, smooth, straight, clear road with slow traffic and simply refuse to accept that such a thing only exists in the land of unicorns and fairies.
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May 6, 2021 21:19
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wolrah posted:And of course there's also the people who want a wide, smooth, straight, clear road with slow traffic and simply refuse to accept that such a thing only exists in the land of unicorns and fairies. Related: The people who get pissy at the idea of having on-street parking instead of huge parking lots that stay 80% empty most of the time. They don't care whether or not it's actually better for businesses, they just think it feels more crowded/worse.
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May 6, 2021 21:29
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Haifisch posted:Related: The people who get pissy at the idea of having on-street parking instead of huge parking lots that stay 80% empty most of the time. They don't care whether or not it's actually better for businesses, they just think it feels more crowded/worse. Sort of related question, but how do traffic engineers look at parking garages? Those seem to be the best of both worlds - no need for massive parking lot footprints, and none of the "clutter" of street parking or additional traffic from people circling for spots.
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May 6, 2021 21:36
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AreWeDrunkYet posted:Sort of related question, but how do traffic engineers look at parking garages? Those seem to be the best of both worlds - no need for massive parking lot footprints, and none of the "clutter" of street parking or additional traffic from people circling for spots. Not sure about how traffic engineers look at them, but structural engineers look at them as expensive.
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May 6, 2021 21:43
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dublish posted:Not sure about how traffic engineers look at them, but structural engineers look at them as expensive. Even accounting for public costs/benefits? The structure may be expensive to build, but if they allow for more density that also means more tax revenue and more efficient public services. To be fair that's out of scope for a structural engineer. Most transport infrastructure is run at a loss, but we do it anyway because it enables the rest of the economy/society.
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May 6, 2021 21:49
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I always wonder how much bad bicycle infrastructure in the US exists because it was required to be built as a condition of the funding source rather than because anyone actually thought something like this was a good idea. This feels like the cycling equivalent of an ADA-compliant bus stop on a road without sidewalks.
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May 6, 2021 21:55
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AreWeDrunkYet posted:Even accounting for public costs/benefits? The structure may be expensive to build, but if they allow for more density that also means more tax revenue and more efficient public services. To be fair that's out of scope for a structural engineer. Architects hate garages unless they're underground (with something else on top). Because they create dead plots of land, like parking lots, only smaller. And aesthetically because they are hard to make into anything remotely pretty. Motorists dislike them because they feel less safe than an open lot. I'm pretty sure there are more break-ins in cars in garages, but I don't have numbers to back that up. I doubt a traffic engineer would even have an opinion.
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May 6, 2021 22:07
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lavaca posted:I always wonder how much bad bicycle infrastructure in the US exists because it was required to be built as a condition of the funding source rather than because anyone actually thought something like this was a good idea. This feels like the cycling equivalent of an ADA-compliant bus stop on a road without sidewalks. This is like an ADA compliant bus stop in the middle of a six lane divided highway with no crosswalks. Florida is the worst.
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May 6, 2021 22:41
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AreWeDrunkYet posted:Even accounting for public costs/benefits? The structure may be expensive to build, but if they allow for more density that also means more tax revenue and more efficient public services. To be fair that's out of scope for a structural engineer. I remember hearing that parking garages have a lifespan 10-20 year lifespan, lower if theres significant winter, from being exposed to the elements and having to hold heavy loads.
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May 6, 2021 23:21
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Hippie Hedgehog posted:Architects hate garages unless they're underground (with something else on top). Because they create dead plots of land, like parking lots, only smaller. And aesthetically because they are hard to make into anything remotely pretty. So do architects prefer parking lots? Those are far worse aesthetically by any measure. Of course in an ideal world cities would cut back on the number of parking spots, but I mean as an alternative to the parking lot vs street parking discussion above. Parking garages are not a replacement for public transport, just a way to put as many spots as possible in the smallest footprint. The safety thing is an interesting point, but again it's not like parking lots, especially large ones, are particularly safe. A lot of them have emergency call stations because of that danger. I'd also wonder about break-in stats considering garages can be more effectively blanketed with cameras and have limited entrance/exit points. And why wouldn't a traffic engineer have an opinion? Parking options have an impact on traffic flow and patterns. Parking lots mean longer travel distances between locations, and street parking means fewer traffic lanes (or artificially wide streets) and additional traffic from people circling for parking. Communist Zombie posted:I remember hearing that parking garages have a lifespan 10-20 year lifespan, lower if theres significant winter, from being exposed to the elements and having to hold heavy loads. A parking lot also has a lifespan of about 20 years. Google suggests 30+ years for garages. Honestly surprised about all the parking garage hate here considering the available alternatives for parking. AreWeDrunkYet fucked around with this message at 23:48 on May 6, 2021 |
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May 6, 2021 23:44
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lavaca posted:I always wonder how much bad bicycle infrastructure in the US exists because it was required to be built as a condition of the funding source rather than because anyone actually thought something like this was a good idea. This feels like the cycling equivalent of an ADA-compliant bus stop on a road without sidewalks. It's exactly this. Florida state statute says any road resurfaced with state dollars has to have bike lanes. Cheapest method for doing this is to stripe a three foot segment of the shoulder as a "bike lane." If you have the real estate, you can narrow travel lanes to create a buffered bike lane (the ones with the double line, like the ridiculous one posted above). Safer than a standard lane? Nah, not really. Still going to have cyclist fatalities on any road with traffic at or above 35 MPH, unless you properly grade separate cyclists from cars with something like a multi-use trail. 
Varance fucked around with this message at 03:23 on May 7, 2021 |
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May 7, 2021 03:07
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