Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Is Every Speed Limit Too Low?

priceonomics.com

Post reply on HN
Print view View original

81–90 of 214 posts

Re: Is Every Speed Limit Too Low?

#81

Post by TeMPOraL »

ameister14 wrote: post #71
peatmoss wrote: post #15

This article ignores a lot of peer-reviewed literature from planning, public health / injury prevention, and civil engineering in favor of some folksy wisdom of a lieutenant cop. A good starting mental model is that vehicle speeds increase both the frequency and severity of crashes. The article weakly, and quietly made an argument that I do agree with. Namely, roadway design needs to accompany speed limits to ensure…

I think it's pretty interesting that you advocate for narrower roads and short setbacks because you belive that on roads like this people are less likely to speed. I don't know if people are less likely to speed on those roads; I think it is unlikely because growing up in a small town, people speed on backwoods roads all the time. Still, I'm not sure that this is the case. What I do know is that roads like that are l…

Risk compensating behaviour[0] is a real thing; the question is whether that effect is significant in any particular case. Making the roads look less safe will make people drive more carefully, but it has to be shown whether this will cause a net decrease of actual crash rate.

[0] - http://en.wikipedia.org/wiki/Risk_compensation

Re: Is Every Speed Limit Too Low?

#82

Post by bryanlarsen »

IIRC, Sweden has had a "zero pedestrian deaths" goal for the last 10 years or so. Part of that policy was road design, but another pillar was the reduction of urban speed limits to 18 mph, and vigorous enforcement of such.

The number of accidents did not drop substantially, but what did drop was the severity of the accidents. An accident that would have been a fatality in the past is now a broken leg or two.

Re: Is Every Speed Limit Too Low?

#83

Post by dragonwriter »

gaius wrote: post #74
reitanqild wrote: post #67

Earlier quoted context omitted.

Mentioned this in another thread and I'm still looking for researh around this topic: A Dutch engineer once told me (back before 2004 I guess ) that they once raised the speed limit on the roads in Netherlands and found that counterintuitively, - average speed decreased. His explanation IIRC was that 1. once people break the rules it doesn't matter how much and 2. when speed limits felt more correct more people respe…

Let's not forget that the speed limit was never about safety. It was about saving fuel in an oil crisis.

> Let's not forget that the speed limit was never about safety. It was about saving fuel in an oil crisis.

The establishment of the national maximum highway speed limit of 55mph was about that. Speed limits more generally (which predate that by quite a long time), not so much.

EDIT: As it has been accurately pointed out that the above response is US-centric, more generally: the establishment of reduced speed limits in many jurisdictions in the early-mid 1970s (including the US national maximum highway speed limit of 55mph) were due to the concerns of saving fuel in an oil crisis, but that is not true of speed limits more generally (either before -- stretching back to more than a century before automobiles existed -- or after the 1970s.)

Re: Is Every Speed Limit Too Low?

#84

Post by aetherson »

nostromo wrote: post #17
wahsd wrote: post #7

Earlier quoted context omitted.

It doesn't even make any sense regarding highways. Ignoring their embarrassingly flawed standard for setting speed limits based on a percentile of speed limited traffic, there are so many other factors that go into the danger of traffic that are wholly and totally separate from speed. I would argue that the speed is exponentially less significant than the skill and training and experience of the drivers. Take a compa…

Per-capita is a bad way of measuring auto-fatalities. The US is very spread out and requires a lot of driving. For example, just driving from SF to LA requires more driving than Cologne to Berlin. Per mile driven is much better, and it narrows the US gap with other countries substantially. (The US is slightly lower than Japan, slightly higher than France.)

Per mile is much better, but also not that good. There are a lot of variables here. How much of driving is at freeway speeds versus how much at lower speeds (where even worse accidents are less likely to cause fatalities)? How good is trauma care in that country (which can turn what would be a fatality in country A into an injury in country B -- and note that part of how "good" trauma care is has to do with how remote from a hospital traffic accidents are)? How modern are vehicles in that country, and what percentage are what kinds of vehicles (air-bag equipped modern cars are much safer than older cars, which are in turn much safer than motorcycles)? What kind of intersection traffic control is there? How good are the roads?

Re: Is Every Speed Limit Too Low?

#85

Post by TeMPOraL »

dragonwriter wrote: post #75
peatmoss wrote: post #64

Earlier quoted context omitted.

Generally, worth taking government reports with a grain of salt. I've participated in a few, and the standards are often much lower than peer-reviewed articles. That said, on a quick skim, I don't see anything that strikes me as being obviously wrong / overturned (FHWA was 1997). But, I also don't see either source providing justification for driving faster. Both reports seem to accept this (in fact, this is about as…

> If people respond to a combination of law and roadway design (perhaps leaning more heavily on the latter), and we want behavior in line with law, what should we do? Ease the law or change the roadway design? Or change the context in some third way (e.g., enforcement)? The thing with roadway design is that the roadway designs which enourage higher speed are generally the same ones that are safer at any given speed,…

That's why I'm for average speed traffic cams and ruthless, fully automatic ticketing of speeders. When the probabilty of getting caught and punished reaches almost certainity, people start to "factor it in regular behavior calculations".

But this is going to be a hard sell for both drivers (who feel entitled to their high speed) and law enforcement (which treats ticketing as a revenue source; widespread deployment of such system would dry up the money stream almost immediately).

Re: Is Every Speed Limit Too Low?

#86

Post by skrause »

cfstras wrote: post #44

Disclaimer: I am from Germany. The speeding system we have here seems to make a lot more sense to me: On most highways, there is no speed limit. The only (theoretical) limit is the motor limitation of 155 mph (250 km/h), which can be taken out, but will almost always lead to losing any kind of motor warranty. In practice, there are limiting signs to 75 mph (120 km/h) for passages where the road is not good enough or…

I'm also German and I would like to have a general speed limit on highways.

Your theory sounds all nice and works if you drive on empty roads, but as soon as there's a bit of traffic the lack of a speed limit results in a very stressful and uncomfortable driving.

The main problem is the speed difference between the individual lanes. On the right lane you have the trucks which are limited to 90 km/h by law, so that's the maximum speed you can usually drive on that lane. Now most highways only have two or three lanes. No speed limit usually results in a difference of at least 40 km/h between lanes and always-changing speeds because of traffic. Driving in a small car with a low-power engine is no fun at all, your only choices are getting stuck behind trucks at 90 km/h or a constant speeding up, slowing down, switching lanes and pushing your car to its limit.

My personal theory is that this is one of the main reasons why German drivers are so aggressive. The drivers most in favor of no speed limit are usually also the most aggressive.

Re: Is Every Speed Limit Too Low?

#87

Post by DSMan195276 »

dfxm12 wrote: post #70
incision wrote: post #24

Earlier quoted context omitted.

>'That's (supposedly) because a ticket for anything less than 10mph is simply not worth it for the cops.' Depends on your cops. I've witnessed tickets for 5 over (40 in a 45), 4 over (49 in a 45) and a stop, thankfully without a ticket for 1 over (31 in 30). I'm given to thinking of it as a lottery. Someone is getting pulled over, today me, tomorrow someone else. I'm just glad I haven't had a case of 'marijuana smell…

Where are these slower roads though? If I were a cop, I'd be much more likely to pull people over for speeding in more residential areas, which tend to have these sub-55 speed limits.

I agree. Going 10 over on the freeway/highway hardly matters for the most part because it's not like that 10 mph is the difference between being able to or not able to stop if something runs out in-front of your car, you're already going at least 65 mph anyway. It's a different situation if it's a smaller road or a side-street with lots of houses around. Going 25 vs. 35 could very well be the difference between being able to stop fast enough if a kid runs out on the road.

Re: Is Every Speed Limit Too Low?

#88

Post by AnthonyMouse »

TeMPOraL wrote: post #81
ameister14 wrote: post #71

Earlier quoted context omitted.

I think it's pretty interesting that you advocate for narrower roads and short setbacks because you belive that on roads like this people are less likely to speed. I don't know if people are less likely to speed on those roads; I think it is unlikely because growing up in a small town, people speed on backwoods roads all the time. Still, I'm not sure that this is the case. What I do know is that roads like that are l…

Risk compensating behaviour[0] is a real thing; the question is whether that effect is significant in any particular case. Making the roads look less safe will make people drive more carefully, but it has to be shown whether this will cause a net decrease of actual crash rate. [0] - http://en.wikipedia.org/wiki/Risk_compensation

> Making the roads look less safe will make people drive more carefully, but it has to be shown whether this will cause a net decrease of actual crash rate.

There is also the matter that many of the ways to make roads look less safe would in actual fact make the roads less safe. At a given speed, narrower lanes increase the probability of a collision. Parked cars on the side of a road increase the probability that one will be hit, or conceal from motorists the presence of pedestrians about to step into the street.

People focused on speed are asking the wrong question. The question is not "how do we get people to slow down" but rather "how do we make the roads safer"? Speed is only one variable.

Re: Is Every Speed Limit Too Low?

#89

Post by gaius »

dragonwriter wrote: post #83
gaius wrote: post #74

Earlier quoted context omitted.

Let's not forget that the speed limit was never about safety. It was about saving fuel in an oil crisis.

> Let's not forget that the speed limit was never about safety. It was about saving fuel in an oil crisis. The establishment of the national maximum highway speed limit of 55mph was about that. Speed limits more generally (which predate that by quite a long time), not so much. EDIT: As it has been accurately pointed out that the above response is US-centric, more generally: the establishment of reduced speed limits i…

You know there are cars outside America?

http://news.bbc.co.uk/onthisday/hi/dates/stories/december/15...

Re: Is Every Speed Limit Too Low?

#90

Post by [deleted] »

peatmoss wrote: post #15

This article ignores a lot of peer-reviewed literature from planning, public health / injury prevention, and civil engineering in favor of some folksy wisdom of a lieutenant cop. A good starting mental model is that vehicle speeds increase both the frequency and severity of crashes. The article weakly, and quietly made an argument that I do agree with. Namely, roadway design needs to accompany speed limits to ensure…

[deleted]
Post reply on HN