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Almost every speed limit is too low (2017)
- telotortium 8y agoGiven this article's argument (the speed of traffic is largely independent of the speed limit, and depends more on the road itself), the logical path to decreasing road speeds is https://en.wikipedia.org/wiki/Traffic_calming https://en.wikipedia.org/wiki/Traffic_calming. In my experience, California residential streets are especially egregiously bad in road design, having wide streets (often approaching 2 full lanes per direction, although the outer "lane" is unmarked and used for street parking) that suggest a speed 15 mph or so greater than the speed limit.
- wolrah 8y agoThat is 100% correct. If you build a 50 MPH road through a neighborhood, you're going to get 50 MPH traffic through a neighborhood. What the signs say is irrelevant unless there's a cop right there. If you want slow traffic, build slow roads. Likewise, if you build your house on a fast road, don't expect traffic to slow down just because your kids are there.
- notatoad 8y agotraffic calming measures in residential streets have so many benefits. bulb-outs not only slow traffic, they reduce pedestrian crossing distances. street trees slow traffic by making the street seem visually narrower to drivers without actually narrowing the street, and also create shade, improve property values, and regulate temperature.
- mzs 8y agoUntil the ladder truck can't negotiate the corner.
- masonic 8y agoPeople downvoting this need to learn from history. The Oakland Hills fire[0] was made far more lethal than it should have been because the narrow, vehicle-clogged roads prevented fire trucks from ascending the hills. [0] https://en.wikipedia.org/wiki/Oakland_firestorm_of_1991 https://en.wikipedia.org/wiki/Oakland_firestorm_of_1991
- bobthepanda 8y agoIt‘s worth noting that Europe has lots of small winding roads and is not noticeably more dangerous in terms of fire safety. In fact, what has happened is that average fire truck size in the US is much larger than in Europe, and that is what drives the requirement for wider streets. https://www.citylab.com/transportation/2018/12/fire-trucks-engines-emergency-vehicles-too-big-for-cities/577735/ https://www.citylab.com/transportation/2018/12/fire-trucks-e...
- mzs 8y agoOr the subdivision I used to live in where right before they moved the city hall across the street they tore-up the landscaping in the middle of the entrance and bulges on the sides near intersections for this reason. For a few years it was this way, fortunately there was no fire in the meantime. They added more speed humps in the process.
- deleted 7y ago[deleted]
- Doxin 7y agoWhere the obvious solution is to build less obscenely oversized firefighting vehicles.
- tomatotomato37 8y agoI agree traffic calming is a very useful tool in making streets safe, but I also want to bring attention to this picture found in the gallery of that page and how it relates to the basis of the original article. https://en.wikipedia.org/wiki/Traffic_calming#/media/File:Directional_closure_violation.jpg https://en.wikipedia.org/wiki/Traffic_calming#/media/File:Di...
- xvedejas 8y agoThere are many counter-intuitive effects in traffic engineering. Widening lanes has often been done in the name of safety, but the effect is that drivers feel safer driving faster, and the rates of deadly crashes rise. This suggests to me that to make roads safer, we might want to design them so that drivers feel they need to drive slower and more safely. Narrow the lanes where they are too wide, add roundabouts instead of multi-level exchanges, allow tighter curves. Especially useful for cities, since these changes would give back land for non-highway uses.
- lostphilosopher 8y agoSimilar to a phenomenon in sports - more and better protective gear leading to more aggressive play leading to more injuries instead of the expected less.
- lostphilosopher 8y agoAKA "The Peltzman Effect" - https://en.wikipedia.org/wiki/Risk_compensation#Peltzman_effect https://en.wikipedia.org/wiki/Risk_compensation#Peltzman_eff... Was too busy to cite sources at the time, but for posterity: https://www.nytimes.com/2017/01/06/opinion/the-dangers-of-safety-equipment.html https://www.nytimes.com/2017/01/06/opinion/the-dangers-of-sa... https://www.usatoday.com/story/sports/ncaaf/2013/07/30/concussions-college-football-nfl-guardian-caps/2601063/ https://www.usatoday.com/story/sports/ncaaf/2013/07/30/concu... https://sports.cbslocal.com/2015/07/03/lemco-why-football-needs-less-pads/ https://sports.cbslocal.com/2015/07/03/lemco-why-football-ne...
- birdman3131 8y agoI don't know how many time roundabouts and gps have caused near dangerous split attention that just does not happen with normal stoplights. They may be better for local traffic but for anybody from out of town they are worse.
- notatoad 8y ago>Roundabouts reduced injury crashes by 75 percent at intersections where stop signs or signals were previously used for traffic control, according to a study by the Insurance Institute for Highway Safety (IIHS) https://www.wsdot.wa.gov/Safety/roundabouts/benefits.htm https://www.wsdot.wa.gov/Safety/roundabouts/benefits.htm
- okket 8y agoPrevious discussions: https://news.ycombinator.com/item?id=14196812 https://news.ycombinator.com/item?id=14196812 (2 years ago, 725 comments) https://news.ycombinator.com/item?id=8133103 https://news.ycombinator.com/item?id=8133103 (5 years ago, 207 comments)
- robrtsql 8y agoI am all for raising the speed limit if the speed limit is lower than what is safe, but I have an issue with the way the article blames drivers who drive at the speed limit for the delta in speeds. If we all need to agree on a speed to drive, why not choose the one that we can drive at without risking being pulled over and ticketed?
- ronsor 8y ago"It's too slow"
- wolrah 8y agoBecause a road has a natural speed, and that's what most people will drive at when they're not actively thinking about it. If the speed limit is below that natural speed, you end up with most drivers going faster while the few follow the absurd rule.
- bryanlarsen 8y agoThe problem is that the "natural speed" for a road is based on a human brain's subconscious calculation. And the human brain is very bad at doing that for any speed faster than a good runner can go.
- bluGill 8y agoActually the human brain is good at finding the natural speed. Many roads have a natural speed that is higher than the safe speed and this is a problem. When the road itself says drive some speed the human brain is not good at reading that the road is tricking it and the safe speed is slower. The above is a failure of engineering. It has been well studied in academics, but few actually account for it.
- robrtsql 8y agoIs it absurd to not want to get pulled over? I'm not arguing against raising the speed limit to the natural speed. I'm against blaming (and tailgating and generally harassing) drivers who are following the speed limit because they don't want to have to pay a fine. It seems like the blame is misplaced.
- pnutjam 8y agoSpeed limits should be set fast enough that nobody should reasonably break them, and then strictly enforced. In town, 40 mph, if your caught speeding your car is impounded. Highway, speed limit, 120mph. If your speeding, your car is impounded.
- greedo 8y agoIn a residential area? You come through my neighborhood at 40 and I'll go all Garp on you.
- wolrah 8y agoIf your neighborhood has roads built for a natural speed of 40 MPH, take it up with whoever built the roads. If you want slow traffic, build slow roads. If you build fast roads, you get fast traffic. No silly sign changes that.
- bryanlarsen 8y agoResidential roads should be built so ambulances and fire trucks can go fast. Everybody else should drive slow because they don't want to kill a child.
- bluGill 8y agoAmbulances and fire trucks don't need to go fast on residential streets. The difference between fast and slow for those short distances isn't significant even when second count. Of course residential streets should connect to faster highways quickly for that to work.
- aidenn0 8y agoMy neighborhood has such a road. It's a road that is a collector road between two highways and a residential road outside of those two highways. However the total width of the road is approximately the same, despite there being more lanes in the collector portion. I've actually seen cars slow-down when moving from the 25MPH zone to the 45MPH zone due to the greatly reduced shoulder area in the 45MPH zone, but most cars go about 35-40MPH on both sections.
- rhinoceraptor 8y agoI love the higher speed limits in northern Michigan (75 for freeways, 65 for highways). There's no reason for a highway to be so slow when there's miles between driveways and intersections.
- hcho 8y agoNot a word about carrying capacity of junctions, exits, etc... Safety is a secondary concern when it comes to speed limits.
- DeRock 8y agoThe premise of the article is that the speed limit is uncorrelated with the speed of traffic, other than a small (10%) group of drivers. Therefore reducing the speed limit to eg. Reduce flow into a junction, doesn’t work, people will continue to drive the speed they are comfortable with.
- cfmcdonald 8y agoIs this whole article premised on this one guy's intuition that speeding must be safe because we aren't all dead? There are actual studies on this stuff based on the changes in U.S. federal speed limit rules in the 70s and then again in the 90s. They are not conclusive but do suggest that higher speed limits lead to more fatalities: https://en.wikipedia.org/wiki/National_Maximum_Speed_Law#Safety_impact https://en.wikipedia.org/wiki/National_Maximum_Speed_Law#Saf...
- aaomidi 8y agoThose studies are useless when compared to literal death rates in roads with higher speed limits. More people died in Montana after they were forced to put real speed limits on the roads, with police enforcement: https://www.motorists.org/press/montana-no-speed-limit-safety-paradox/ https://www.motorists.org/press/montana-no-speed-limit-safet... The German autobahns are extremely safe compared to their other roads. The US interstate system can easily support "Reasonable speed limits" on most of their roads - its flat and straight. These studies don't take into consideration what actually happens when some people decide to follow the law and some people decide to travel at the road's natural speed. That delta is the cause of so many accidents.
- commandlinefan 8y agoSpeed limits are set deliberately low so that police departments can collect fines whenever they need to buy a new cruiser.
- xfitm3 8y agoThis. Speeding kills, your pocketbook. https://youtu.be/2BKdbxX1pDw https://youtu.be/2BKdbxX1pDw
- furyofantares 8y agoI wonder if there's an unfortunate thing going on where it's not really about the number posted, it's about going faster than the people around you. Driving is a lot easier and less stressful if you're going faster than everyone else. You really only have to worry about the stuff in front of you that you see all the time, and as soon as you pass someone they are no longer a concern. Similarly it takes a lot more attention if everyone is going faster than you. So there's always an incentive for each individual to speed up a little.
- dsfyu404ed 8y agoI think you're giving people way too much credit. Most people aren't paying attention to traffic behind and beside them even when they're the slow car.
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- fooblitzky 8y agoI find it's the opposite - when you're traveling faster than the average, you are constantly adjusting your speed or having to change langes, as you come up on traffic from behind. You also get frustrated at nearly every car that slows your progress, especially if they're blocking all lanes. If you're going slightly slower, you can just stay in your lane and cruise. Cars occasionally pass you, but that's it. It's way less stressful. Plus there's always someone going faster than you, no matter how fast you go.
- Noumenon72 8y agoThis comment got downvoted to dead? It's just what I was going to say! Driving slower than everyone else is the closest thing you can get to autopilot.
- rhacker 8y agoTen years ago I would find articles and blog posts about how awful the speeders and tailgaters are in portland. The blog would effectively blame the influx of Californians. Today (and this started about 4 years ago) you do the same search in google and you only find articles about how slow some people drive in Portland and that they are a nuisance to be removed.
- rdiddly 8y agoFormer Californians now outnumber everybody else I guess.
- jld 8y agoPart of the issue is that the speed limit often times dictates how the street is designed. In my city, the default speed limit for city streets was 30mph. Safety advocates lobbied for and achieved lowering that limit to 25mph. The goal was not that cars would immediately all start driving 5mph slower, but rather to direct the city's traffic engineers to start designing the street layout to lower the 85th percentile speed by about from 30mph to 25mph.
- choeger 8y agoInteresting to read about that percentile design. Here in Germany we have (as you probably know) a few hundreds of kms of unlimited Autobahn (advised is 130kph). These roads are way better and safer than the US highways and freeways I experienced, btw.. So it is not a fair comparison. Nevertheless we have a heated debate were many very loud votes in the media demand a speed limit of 120 or even 100kph. Because that is obviously necessary and everything else is stupid. Now, while there are certainly many more or less valid arguments for a speed limit, I have never heard anyone arguing about the number. The verocity of the debate is contrasted by a total lack of arguments for or against a specific limit. Why 120 and not 130 or 90. What about 160? To me it looks like there are many people either offended by or incapable of dealing with other people making different choices. The whole debate seems to be a way to force others into coercion and the actual limit is chosen to coerce as many people as possible. So in Germany the debate seems to target at the complete opposite to define a speed limit at the 15th percentile. That's an intriguing observation. And rather typical for us, tbh.
- dsfyu404ed 8y ago>To me it looks like there are many people either offended by or incapable of dealing with other people making different choices. The whole debate seems to be a way to force others into coercion and the actual limit is chosen to coerce as many people as possible. This observation applies to a hell of a lot of things.
- tomatotomato37 8y agoI think a big source of contention is a failure to clarify what type of road requires change, leading to frustration from people believe someone wants to drop their suburban 45mph artery road with no driveway access to 20, when the other person is just talking about an collector in some dense urban zone. Not to say those people may have a point however; speed cameras always seem to have a mysterious way of appearing on split expressways with a new speed limit rather than the avenue near the school zone that actually requires it.
- Severian 8y agoGermany also has much higher standards for driver education, stiffer fines for infractions, and a safety first approach towards operating heavy machinery. In the US, you can get a license by answering 25 questions, driving around a block, and doing some sort of parallel parking exercise. They pretty much hand them out regardless of actual driving ability. One thing that would reduce the number of crashes in the US is making tailgating and passing lane camping a heavy infraction. To drive safely is to anticipate conditions and expectations. I would also support 10 year renewal testing before age 65, as bad habits quickly become routine. Shorter intervals thereafter.
- psoots 8y agoThere are more reasons to control speed than safety. As the article mentions, Nixon lowered speeds to reduce fuel consumption in the US. Considering the climate crisis, I think that's a motivating reason to have lower speed limits. But as others have mentioned the means of getting people to drive slower or more safely or more efficiently may not be limited to the numbers on the sign.
- jcoffland 8y agoToday's cars are much safer than the cars of the 70s at higher speeds. Not only do they better protect the occupants in an impact but they steer better, break better and are far more stable. Add to that better fuel efficiencies and it's hard to argue that we need the same speed limits. 55 was a response to the oil crisis but it also reflected automobile engineering of the time.
- javagram 8y agoI have a 2010 model car and I still seem to get significantly better gas mileage around 55-65 mph than I do around 70-75, although I haven’t measured it scientifically. Isn’t this a function of wind resistance physics that can’t be solved, just mitigated? As driving automation increases and the threat of climate change and CO2 emissions looms larger, automated cars could drive at current speed limits without getting impatient like a human driver, improving both efficiency and safety.
- lm28469 8y agoIt does. Almost any car will be more efficient around 50-60mph. But it only matters on highway where the bottleneck is due to aerodynamism, at lower speed you might be less efficient at 20mph than 30mph for example. https://en.m.wikipedia.org/wiki/Fuel_economy_in_automobiles https://en.m.wikipedia.org/wiki/Fuel_economy_in_automobiles
- ska 8y agoIsn’t this a function of wind resistance physics that can’t be solved, just mitigated? Yes, this is fundamental; roughly power required is proportional to cubed velocity. Improved coeff of friction helps, but you can't get away from this. Eventually air friction is the completely dominant force. So at highway speeds, absent some rare gearing issues causing inefficient fueling, faster means less efficient. This is also why the fastest "hypercars" are pushing on order of 1000 hp. At lower speeds, all sorts of other issues kick in (and idling is its own issue)
- mywittyname 8y ago
- cm2012 8y ago“I don’t want to lie to people,” lieutenant Megge tells us. It may make parents feel better if the speed limit on their street is 25 mph instead of 35 mph, but that sign won’t make people drive any slower. Megge prefers speed limits that both allow people to drive at a safe speed legally, and that realistically reflect traffic speeds. People shouldn’t have a false sense of safety around roads, he says." This is likely false. NYC changed the speed limit to 25 mph in Nov 2014. Pedestrian deaths have been sharply reduced: 1) https://ny.curbed.com/2018/1/8/16863408/nyc-vision-zero-traffic-pedestrian-fatalities-statistics https://ny.curbed.com/2018/1/8/16863408/nyc-vision-zero-traf... 2) https://www.nytimes.com/2018/01/08/nyregion/nyc-pedestrian-deaths.html?module=inline https://www.nytimes.com/2018/01/08/nyregion/nyc-pedestrian-d... At the same time pedestrian deaths in the US as a whole have increased: https://usa.streetsblog.org/2019/03/01/pedestrian-deaths-reach-another-high-drivers-entirely-to-blame/ https://usa.streetsblog.org/2019/03/01/pedestrian-deaths-rea... The data is clear that lower speeds means accidents are less dangerous: https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain-why-20-mph-should-be-the-limit-on-city-streets/ https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain...
- HBKXNCUO 8y agoIs there any data showing that people are actually driving slower in NYC as a result of the speed limit decrease?
- notatoad 8y agois there any evidence that traffic speeds have actually reduced due to the speed limit change? the vision zero project includes a whole bunch of stuff, including redesigning dangerous intersections, which the decline in pedestrian deaths could be attributed to.
- kolinko 8y agoRegarding your last link - lower speeds and lower speed limits are not the same. Also, your claim that it’s lower speed limits that reduced deaths seems not entirely honest - the articles say that there were more things that changed besides speed limits.
- joe_the_user 8y ago
- francisofascii 8y agoWhat is needed is consistent enforcement. People speed because, most of the time, there are no repercussions. Speed traps feel unfair because they are so rare and arbitrary. A simple solution, blanket our roads with camera speed enforcement everywhere making it consistent and objective. Equip cars with warning lights giving people a chance to slow down before getting the ticket.
- fooblitzky 8y agoThis is absolutely correct. If you want people to start obeying the speed limit, start enforcing it with automated cameras. It works in countries that do it. I still don't really understand the whole revenue-raising argument against enforcing speed limits. If you didn't break the law, you wouldn't have to pay the fine. No one is forcing you to speed.
- rcoveson 8y agoConsistent enforcement is an essential element of the rule of law. It's hard to balance against privacy concerns; it's definitely not obvious which is worse: A police force that can fine almost anybody on the road at any time because almost everyone is breaking the law, or a police force that always knows where your car is. Emotionally, I don't feel as strongly that I have a right to not be tracked when I got out in public as I do that I have a right to equal enforcement. The former seems like a detail of how law enforcement is carried out, the latter seems like a key difference between law and tyranny.
- francisofascii 8y agoI think the privacy concerns are valid but honestly can be mitigated. I think it is worth trying anyway. If things got out of hand, enough people would complain, and the legislature would reverse it.
- topspin 8y ago"A simple solution, blanket our roads with camera speed enforcement everywhere" I can't think of any problem with our traffic system that is bad enough to make your solution desirable. Not traffic deaths, arbitrary enforcement, efficiency... nothing.
- Causality1 8y ago"Excessive speed" is often cited as a factor in vehicle crashes, but I wonder how much of that factor can be chalked up to speeders trying to spot police instead of keeping their eyes on the road.
- dsfyu404ed 8y agoIt's circular logic. They're basically saying that there exists a low enough speed that could have theoretically prevented this. Whether any reasonable person would have been going that speed is another story. Crashes would be a lot less common if vehicles couldn't travel faster than 20mph. Car crashes would cease to exist if vehicles couldn't move at all.
- clairity 8y ago> "This is why getting slow drivers to stick to the right lane is so important to roadway safety; we generally focus on joyriders’ ability to cause accidents—and rightly so—but a car driving under the speed limit in the left (passing) lane of a highway is almost as dangerous." i really wish people would heed this rule about slower cars staying to the right (regadless of speed). if you are not passing the car to your right, you should move to the right until you are, but many people scoot to the left lane and set their cruise control so they can zone out (and possibly occupy their brains with something else like talking to other people). this would not only minimize speed deltas and reduce accidents, but it would also improve throughput as speedier traffic clears out faster. and drivers should never just zone out while operating a machine capable of killing people. in any case, i both agree with the article--i actually think speed limits should be accurately set at the 85th percentile, called "suggested speed" or the like, and decriminalized--and support traffic calming measures in urban areas like narrowing lanes, adding more trees/curves, and making commercial streets mixed use by default.
- dreamcompiler 8y agoI think the "Slower Traffic Keep Right" signs may encourage noncompliance because nobody wants to think of themselves as "Slower." Perhaps a better sign would be "If a car passes you on the right, YOU get the ticket."
- rxhernandez 8y agoMany people also dont want to be considered unnecessarily fast or aggressive. Marines notwithstanding, people tend to be okay with being slower in the high desert area of Southern California.
- jplayer01 8y agoGermany's rule is to stay as far right as possible as long as you don't need to overtake any cars or there aren't any cars ahead of you that are slower than you. It has nothing to do with how slow you are, but everything to do with traffic around you.
- 8y ago
- hawski 8y agoIn Berlin (I don't know if it's different in other parts of Germany) and in Poland the default speed limit in cities is 50kph (~30mph). In Berlin most drivers match speed limits. In Poland most drivers ride at 70kph (~45mph) in cities. But Berlin drivers will drive above speed limits when there is a short section with construction, when nothing apparent is happening on it. Maybe they will take the feet out of gas. But most are not riding with 30kph (~20mph) speed limit in this case. Reasons for the discrepancy between Berlin and Poland is in mentality for sure. But I think that more roads are really set for the speed limit in Berlin than in Polish cities I know. So you can drive faster, but you will just be first on the red light. As they say: slow is smooth and smooth is fast. It certainly helps that the Autobahn network have nice stretches without speed limits. I feel that car in Berlin is really just to go to the highway and not to move through the city itself. The limits just picture the priority of public transport and bicycles in city planning. What's funny is that I like to drive more in Berlin than in Poland. It's smoother and drivers seem more used to interruptions. Even though I still drive more in Poland and don't really need a car in Berlin. However parking is pain in whichever country I am.
- bryanlarsen 8y ago"It may make parents feel better if the speed limit on their street is 25 mph instead of 35 mph, but that sign won’t make people drive any slower" Just changing the sign doesn't make people drive slower, but if you actually enforced those speed limits people would slow down and pedestrians would stop dying. Traffic calming may be a cheaper way of slowing people down than enforcement.
- speeder 8y agoI am from Brazil, that for some reason unknown to me went along USA speed limits. I started driving more or less recently and my town has several speedtraps, and they make me unsafer, becuase I am not used to driving a lot yet, I tend to respect speed limit all times, because I don't know where the speedtraps are, this has some consequences: 1. LOTS of honking when I am 5kph slower than the limit... 2. Because of the point 1, I tend to stick to the limit, this mean I am often looking at my speedometer instead of the road, and almost crashed because of this more than once. 3. Often I am overtaken in ridiculously crazy ways, like people overtaking in the opposite direction lane, or during corners, or more than once motorbikes overtaking me using the gutter, passing between my car and the sidewalk. 4. Also a couple times I almost crashed on the rear of experienced drivers that were speeding and I don't noticed, andwent along with the flow, only for them to suddenly slam on brakes right before the speedtraps (only to just as suddenly accelerate again right after them). 5. Often lanes end with strange speed discrepancies, sometimes in unsafe situations, for example there is a one-way road in my town that is in a steep hill that has a curve toward the right, often the left lane is full of people trying to overtake the entire right lane that is following speed limit, and the railings on the outer side of that curve are full of marks of people grinding on them. I've seen once a group of 10 or so cars that were speeding slightly try to overtake a car that was following speed limit only for the first one of the group to crash on the rear of a bus that was on a bus stop when he tried to overtake from the right side (the other 9 or so cars squeezed themselves between the crash and the cars that stopped on the left lane while braking... lots of screeching).
- TheCoelacanth 8y agoAbsolutely false. Increased speeds have a direct causal link to increased severity of injuries and likelihood of fatalities. The speed limits aren't too low, the roads are improperly designed for the speed limits that they have.
- thinkling 8y agoThe article mentions that the 55mph speed limit was pushed by the Federal Government during the 1973 oil crisis to reduce gas consumption... ...but doesn't take the next step to point out that in our era of reducing climate emissions it might make sense to drive a little slower if you're not in a hurry to get there. Owning an electric car makes it very obvious how much smaller your range is when you drive 70-75mph than it is when you drive 50-55mph. I'm sure people will respond to point out that these kinds of individual choices about behavior are noise in the fight against climate change. But maybe you're arguing for a renewed 55mph speed limit, then?
- bluGill 8y agoDriving slow in the left lane is a problem. Driving slow in the right lane doesn't seem to be a bit problem. Germany has sections of the autobahn with very large speed variances, but they are aggressive about enforcing the slower traffic keep right rules so fatalities low.
- vonmoltke 8y ago> Owning an electric car makes it very obvious how much smaller your range is when you drive 70-75mph than it is when you drive 50-55mph. I got optimal fuel consumption in my Acura CL at an average speed of about 65 MPH. That maximal efficiency point varies from vehicle to vehicle, particularly across different vehicle classes.
- thinkling 8y agoI've heard that idea for a long time and have wondered about it: drag (air resistance) is dependent on the square of the velocity and in highway cruising where you're not accelerating, overcoming drag is a huge part of energy expended. How can the engine be tuned to be so inefficient at lower speeds that it somehow gets better fuel efficiency at higher speeds? And if that was ever a thing with older engines, is it still a thing with modern fuel-injected engines that sense performance and adjust fuel injection to optimize?
- lm28469 8y ago"Speeding and traffic safety have a small correlation." You know what doesn't have a _small_ correlation? Speeding and efficiency. Above 60mph almost any car lose an insane amount of efficiency due to aerodynamic drag. I'm all for raising the speed limit but we should get rid of ICE before doing so.
- moron4hire 8y agoSpeed limits in pedestrian-heavy urban areas and children-heavy residential areas absolutely have to be no more than 25mph. The difference in survivability stats for pedestrians struck at 25 vs 35 are stark. What we need are narrower roads, pedestrian islands at intersections, and harsh enforcement. On highways, it doesn't matter. Survivability between 65 and 75 or even 85 is not that much different. You're going to have a really bad day regardless of speed. Far more important is longer ramps, higher vehicle inspection standards, and higher licensing standards. We also need to get long-haul shipping off the roads and back on the rails.
- bluGill 8y agoIt isn't speed limits, it is road design. A well designed road would ensure residential streets wouldn't be driven at faster than 25mph, no enforcement needed.
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- rags2riches 8y agoHighway speed still matters for reaction and braking distance.
- jonstewart 8y agoGenerally when drivers "feel" that a speed limit is too low, it's because the street/road has been over-built. It urban environments, it's inarguable that lower speeds result in fewer fatalities. There's a hockeystick increase in the rate of fatality with pedestrian crashes as vehicle speed increases from ~30mph to ~40mph. See https://nacto.org/docs/usdg/relationship_between_speed_risk_fatal_injury_pedestrians_and_car_occupants_richards.pdf https://nacto.org/docs/usdg/relationship_between_speed_risk_... [PDF]
- dgzl 8y agoI'm certain that in at least some cases, speed limits are kept artificially low so officers have an easy reason to pull someone over. This is done to give officers an opportunity to inspect you for other violations. I'm also certain that if one day every driver made nothing but legal driving maneuvers, the world would shut down before lunch.
- unilynx 8y agoAs the article says, people will drive at the speeds that feel safe... in the Netherlands, more and more roads are redesigned for that. Bumps, parked spots, narrowings and removal of (dividing) lines/road markings are used to bring the traffic back to its intended speed.
- SOLAR_FIELDS 8y agoI live in Texas near SH 130 which is (in)famous for having the highest speed limit posted in the nation (85mph) I think only on the Autobahn can you legally go faster anywhere in the world. In the end you have the normal rabble rousing in the news cycle whenever there is a fatal crash (anecdotally uncommon) but would love to see some statistics comparing SH130 Crashes and fatality rates to other roads in US or world. Some cursory googling does not reveal any studies of this caliber unfortunately.
- Noumenon72 8y agoI can easily believe only 10% of drivers look at the speed limit and drive that speed. But I would have thought that 70% of drivers look at the speed limit and drive some safe margin over -- either +7 mph, or +15 mph. This behavior would be driven by the size of the speeding ticket. Hard for me to believe that none of those people speed up when the speed limit goes up 10 mph.
- pergadad 8y agoThats is an odd article seemingly based on an informal rule applied when revising limits and the officer's personal perception/experience. It even cites scientific evidence to the contrary but simply dismisses it by pointing to the personal experience of the expert. Here's a personal experience: driving in Belgium, the Netherlands or any other country with limits is much more pleasant than driving on German motorways, where you have 40-50% of roads with no limit whatsoever. The high limit means even as drivers tend to be much better trained than in most other countries I've driven, German traffic is unpredictable. You'll overtake a truck driving 90kmh, while yourself driving 130kmh (advised speed) and someone comes up behind you with >170kmh. Changing lanes is much more stressful than eg Belgium which has pretty bad drivers, but they all stick close to the limit of 120kmh, meaning flow of motorway traffic is much more steady. If the issue really were that drivers don't stick to the limit - enforcement is the answer. Increasing limits does not improve safety on its own.
- pry86 8y agoWhat exactly is unpleasant in Germany? If you have a guy suddenly behind you then most likely you didn't check properly in the mirror, and estimated speed of approaching car wrongly. You could also perform overtaking manoeuvre more dynamically, just increase the speed when overtaking and reduce after. Last few months I drive to work on the Germany motorway, and what I can see so far is terrifying. Not fast drivers are the problem but the poor and ashole drivers: - Poor drivers: Me 140/160 km/h, other 120 km/h, and suddenly he/she is changing the lane (to overtake another car ofc), no blinker (you honk at them and they show you the middle finger), nothing! Or switching the lane when when there is not enough space. Jeeez, no! Because you annoyed to drive 117 km/h behind the truck, don't put others in danger. Not everybody in Germany drives 170 km/h or more. So there will be place for you as well, just wait some seconds. Or predict, you see the slow truck in advance, change lane a bit earlier, or show blinker earlier (I always slow down I you give me enough time). Ah, and damn left lane lovers. You overtake them from the right (although you shouldn't) and then they realise "oh shit, I should be in the right one". - Ashole drivers: Driving bumper to bumper even with high speeds, or swaying left to right just to how "hey, I'm behind you" and make a pressure on you. To summarise, after driving in Germany for 8 years, I love it. I like the discipline although on the motorways is getting worse imho. I'm assuming because of immigration from other countries which don't have good driving habits. For me unpleasant was driving on motorways in San Francisco area (madness, and not just because of number of lanes), but I was there only for a few days, so maybe my impression is wrong.