Is Every Speed Limit Too Low? • Hacker News Board

Re: Is Every Speed Limit Too Low?

#121

Post by ajmurmann » Mon, Aug 04, 2014, 10:49 PM UTC

arthurdenture wrote: post #14

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…

> The USA's per capita automobile death rate is over twice as high as Germany's, in spite of speed limits in general being lower in Germany and there being far more and more generous roads in the USA. [...] Statistically speaking though, you would think that more driving on wider, bigger roads and in less densely populated areas would lead to less accidents and not more. The relationship between forgiving roads and s…

I agree completely that traffic engineering is much better in Germany and makes a huge difference. Roads are better sign posted, on ramps are very generous. As I mentioned elsewhere in Germany you are also not allowed to overtake on the right on the Autobahn. So there is a huge push for slow drivers to stay on the right and cars are nicely sorted by speed. Therefore you need to relatively rarely change lanes whereas in the US people will constantly change lanes on freeways especially in busy places like LA. That not only leads to higher risks and makes driving more aggravating, but also slows everyone down. It happens quite frequently here that I will be on a 3 lane freeway and there are three slow cars next to each other. That would be unthinkable. I believe that this allows the German Autobahn to serve more cars than freeways in the US while having in average fewer lanes. I always have this metaphor in my head where I think of it similarly to a Ethernet cable that can now submit more data because the protocol allows for fewer collisions etc.

Re: Is Every Speed Limit Too Low?

#122

Post by ajmurmann » Mon, Aug 04, 2014, 10:55 PM UTC

skrause wrote: post #86

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…

It depends on the Autobahn. I strongly felt what you described on pretty much any Autobahn around cologne where there always was a lot traffic and many on and off ramps. However, my ride usually would take me from there onto the 44(?) towards Paderborn and there was no speed limit and it was a joy even in an old Golf 2. There were very few on and off ramps and moderate traffic. My car would be able to speed up to ~220km/h over the course of several minutes, but it was so worth it.

Re: Is Every Speed Limit Too Low?

#123

Post by aetherson » Mon, Aug 04, 2014, 11:06 PM UTC

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…

Let me rephrase what I think your argument is:

"I think that we should set speed limits to somewhere around where they are now or lower, and then re-engineer our roads to make it harder for people to speed. This is practical and will save lives, and the evidence supports this."

If I'm reading you correctly, I have a number of problems with it:

1. I don't think it's in any way practical to re-engineer roads on the massive scale that would be necessary to do this. If, as asserted, the majority of people exceed the speed limits the majority of the time, you're talking about re-engineering the majority of roads. That's an enormous project compared to resetting the speed limits.

2. You're a bit light on details about what you would do to make people obey the speed limits, but you list as contributing to speeding "wide lanes, big setbacks, and homogenous environments." Leaving aside homogenous environments (are we now talking about re-engineering not only all of our roads, but also all of our cities in general?), I'm sure that making lanes narrower and setbacks smaller would in fact make people drive slower, but would it actually increase safety compared to the counterfactual of not re-engineering and increasing speed limits? I doubt it. Certainly, I don't see evidence for it.

3. Hidden in here is a question of legitimacy. Are current speed limits a result of a social consensus about the speed/safety tradeoff made by an open society? I don't think that there's any convincing evidence that they are. They appear to be a reaction to OPEC and a revenue model for local governments at least as much as they are about a democratic consensus -- and to the extent that they are about a democratic consensus, they seem to be based on one in which the democracy in general was not aware of the deleterious effects of low speed limits in terms of speed differentials.

So, look, the situation right now appears to be:

a. Roads designed for speed, but with artificially low speed limits leading to inflated danger.

And a couple of possible future policies could be:

b. Roads designed for speed, with higher speed limits leading to reduced danger compared to a.

c. Roads designed for lower speed, with the same or lower speed limits leading to reduced danger compared to either a. or b.

It seems like you've jumped to the conclusion that option c is the right one, but I don't know that it is, even granted that it is the safest option.

Re: Is Every Speed Limit Too Low?

#124

Post by seanflyon » Mon, Aug 04, 2014, 11:09 PM UTC

enf wrote: post #94

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…

Most of the recent research on factors affecting vehicle speeds is summarized in http://onlinepubs.trb.org/onlinepubs/circulars/ec151.pdf In it, Dimauita et al credit every foot of lane width with a 2 mph increase in vehicle speeds, and Wang et al credit each additional lane with a 6.5 mph increase.

How much faster can one drive for every foot of lane width while maintaining the same risk of injury or death?

Re: Is Every Speed Limit Too Low?

#125

Post by seanflyon » Mon, Aug 04, 2014, 11:13 PM UTC

gaius wrote: post #89

dragonwriter wrote: post #83

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. 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...

Which countries were you referring to that reduced their speed limits due to an oil crisis?

Re: Is Every Speed Limit Too Low?

#126

Post by wiredfool » Mon, Aug 04, 2014, 11:17 PM UTC

autokad wrote: post #80

bryanlarsen wrote: post #79

Earlier quoted context omitted.

"raising speed limits does not raise driving speeds on roads" I suspect that's a temporary effect. The speed people are comfortable at is mostly a learned phenomenon. The more they drive fast safely, the more comfortable they feel. Remember when you first started riding your bicycle? 10 mph was super fast and was super scary. And it is; that's faster than the speeds that the human body was evolved to support.

i didnt keep riding bicycle faster and faster and faster. i got to a point where i was comfortable at that speed...

Alternate explanation: You got a point where it's physically very hard to go faster.

Most people who ride motorcycles or mopeds do it faster than they would on a bicycle.

Re: Is Every Speed Limit Too Low?

#127

Post by danielq » Mon, Aug 04, 2014, 11:30 PM UTC

ajmurmann wrote: post #121

arthurdenture wrote: post #14

Earlier quoted context omitted.

> The USA's per capita automobile death rate is over twice as high as Germany's, in spite of speed limits in general being lower in Germany and there being far more and more generous roads in the USA. [...] Statistically speaking though, you would think that more driving on wider, bigger roads and in less densely populated areas would lead to less accidents and not more. The relationship between forgiving roads and s…

I agree completely that traffic engineering is much better in Germany and makes a huge difference. Roads are better sign posted, on ramps are very generous. As I mentioned elsewhere in Germany you are also not allowed to overtake on the right on the Autobahn. So there is a huge push for slow drivers to stay on the right and cars are nicely sorted by speed. Therefore you need to relatively rarely change lanes whereas…

I have been driving 8 years in Germany and then 9 years in the US.

In my experience, driving on US freeways requires less lane changes than on German autobahns. This is mostly due to the facts that in the US everybody is driving about the same speed; in Germany, as mentioned above, if you want to drive faster than the trucks but not fast enough to stay always left, you are constantly switching lanes to overtake people in the second lane. If you want to drive a speed that is lower than the 'general' second lane speed, you even need to go in and out from the truck-lane.

Furthermore, since it is OK to overtake on the right in the US you don't need to change lanes if your lane now goes a little faster than the lane on the left. Even though you shouldn't stay left for a prolonged time if you are [much] slower than the rest (even in the US), it is OK to be overtaken on the right.

Though, I am faster on German freeways (driving around 160-170km/h), I enjoy driving in the US more as it is generally more relaxed.

I somewhat doubt that the German autobahn rules are better with dealing with medium-high-traffic situations than US rules. Would be interesting to see actual data on this claim.

Re: Is Every Speed Limit Too Low?

#128

Post by cpncrunch » Mon, Aug 04, 2014, 11:31 PM UTC

Spooky23 wrote: post #99

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…

End of the day, you shouldn't have laws that 80% of the population breaks during the ordinary course if business. I've found myself in vehicles towing trailers where 65 mph was about as fast as I could go. I continuously had cars passing me. If everyone is a criminal, something is wrong with the law.

They say 85% break the limit, but by how much? According to a 2003 UK study only 25% of people break the 30mph speed limit by more than 5mph, and only 20% break motorway speed limits by more than 10mph.

https://en.wikipedia.org/wiki/Road_speed_limit_enforcement_i...

Re: Is Every Speed Limit Too Low?

#129

Post by cpncrunch » Mon, Aug 04, 2014, 11:33 PM UTC

timbre wrote: post #29

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…

The Priceonomics article's main point is that raising speed limits doesn't (much) raise actual speed, so it's not inconsistent with papers (like the one you linked) that show that increased speed causes more and worse accidents.

Other research shows that raising speed limits increases accidents, and reducing speed limits reduces accidents.

https://en.wikipedia.org/wiki/Speed_limit#Effectiveness

Re: Is Every Speed Limit Too Low?

#130

Post by gdne » Mon, Aug 04, 2014, 11:43 PM UTC

All traffic laws do one thing: increase the likelihood that all drivers behave predictably. Going a certain speed. Stopping at a stop light. Not changing lanes erratically. It's all about being predictable to other drivers so they have time to react to your presence. Being unpredictable is the quickest way to get into a collision. Speeding but being predictable is a lot safer than going the speed limit and swerving erratically.