Is Every Speed Limit Too Low? • Hacker News Board

Re: Is Every Speed Limit Too Low?

#181

Post by TeMPOraL » Tue, Aug 05, 2014, 10:08 AM UTC

Scoundreller wrote: post #156

TeMPOraL wrote: post #85

Earlier quoted context omitted.

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 o…

It would be an easy sell if drivers (such as myself) didn't feel convinced that highway speed limits are arbitrary. 100km/h is a very unlikely number for an engineer to calculate as an upper boundary for a road. It wouldn't be a tough sell to lower speed limits on some portions, and raise it on others, even on a time-neutral but safety-positive basis, but yet, the powers that be stick to their arbitrary number.

> 100km/h is a very unlikely number for an engineer to calculate as an upper boundary for a road.

I haven't seen any actual calculations used for setting speed limits, but I do remember being taught in school (on physics lessons) that if you want maximum road throughput then after factoring in safe distance (which is proportional to square of velocity) you end up with ~50km/h as a sweet spot. Even if some other factors (like fuel efficiency) alter this calculation, 100km/h feels quite plausible to me.

Also I believe that many consider speed limits as arbitrary because most people seem not to care about safe distances anyway.

Re: Is Every Speed Limit Too Low?

#182

Post by Erwin » Tue, Aug 05, 2014, 10:44 AM UTC

huuu wrote: post #172

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…

Off topic but related: almost all roads in The Netherlands are provided with speed detection induction loops. The data is open and there is a nice website showing the top speeds: http://www.bestwelsnel.nl/ (best wel snel = pretty fast)

That map looks like high scores in an arcade game encouraging you to beat them. Can you beat the 276 km/h (!!) or 247 km/h on what seems to be a long tunnel or a bridge?

Is there any documented effect of that data being public to people trying to "beat" the speeds?

Re: Is Every Speed Limit Too Low?

#183

Post by asuffield » Tue, Aug 05, 2014, 10:49 AM UTC

djloche wrote: post #176

I'm an advocate of getting rid of speed limits completely. Rather than having speed limit signs, post signs that suggest the highest speed for reasonably safe driving. If there is an accident that causes you or someone else damage, the court can use those signs as a way to say that you went against better judgment and assign a greater punishment. I'd love to know what the best speed to drive at is, rather than having…

The punishment idea never really seems to deter drivers, and it has one critical flaw: the punishment for driving like a maniac and causing a 10-car pileup that killed a whole bunch of people is already that you didn't survive it either.

Getting bad drivers killed along with several other innocent people is not an acceptable way to solve the problem of road safety.

Re: Is Every Speed Limit Too Low?

#184

Post by mnw21cam » Tue, Aug 05, 2014, 10:57 AM UTC

rokhayakebe wrote: post #153

ackfoo wrote: post #151

The problem with speed limits is that people think they are a license to go that speed, or a little faster, regardless of the conditions. Americans are nearly universally useless at slowing down for things like ice, heavy rain and fog. They ignore things like stopping distance and diminished reaction time in poor visibility. I agree that there is room for debate on speed limits under ideal conditions on well-maintain…

The problem with speed limits is that people think they are a license to go that speed, or a little faster, regardless of the conditions I never thought about it that way, and I agree. Speed limit should DEFINITELY be dynamic depending on weather conditions, location, time, traffic etc...

And in France, they are. The speed limit is automatically lowered in bad weather. Tourists have been fined for not realising.

http://en.wikipedia.org/wiki/Speed_limits_in_France

Re: Is Every Speed Limit Too Low?

#185

Post by TheOtherHobbes » Tue, Aug 05, 2014, 12:09 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…

>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.

More than that, it's pure econo-meta - regulation is bad, freedom is good, if you leave people alone they'll behave responsibly, and everyone wins.

It's a moral parable (for economic values of 'moral') not a peer-reviewed paper.

Here's a newspaper piece that summarises some of the relevant peer reviewed research and draws a different conclusion:

http://www.theguardian.com/news/datablog/2013/may/13/speed-l...

Re: Is Every Speed Limit Too Low?

#186

Post by mseebach » Tue, Aug 05, 2014, 12:24 PM UTC

3pt14159 wrote: post #46

I studied Structural Engineering in University, which was under the Civil program, and, at least in Canada, we don't design for what people will go, but for how drivers can handle unexpected conditions, like cars turning out in front of them, a loss of traction due to ice, and visibility at night. I've also seen multiple studies that show that during high visibility / traction days (summer during the daytime) the spe…

> I've also seen multiple studies that show that during high visibility / traction days (summer during the daytime) the speed limit can be safely raised to at least 130km/h for most highways that are 100km/h.

In France, that's how the law works: http://www.americansinfrance.net/images/Driving_School/Road_...

Re: Is Every Speed Limit Too Low?

#187

Post by aetherson » Tue, Aug 05, 2014, 12:33 PM UTC

cpncrunch wrote: post #129

timbre wrote: post #29

Earlier quoted context omitted.

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

Obviously it's hard to judge studies by one sentence summaries, but some of those papers sound like extraordinary claims. "Speeds declined by 5 km/h. Fatal crashes declined by 12%." Come on, really? We're going to imagine that a 3mph change in speed (at speeds around 80mph) could possibly be causal to a 12% change in fatalities?

Re: Is Every Speed Limit Too Low?

#188

Post by corin_ » Tue, Aug 05, 2014, 12:56 PM UTC

saticmotion wrote: post #65

I didn't get this from the article, but are there no automated cameras in the USA? In Belgium there are tons (I pass 5 on the 10 minute drive to my girlfriend), but they're a joke. If people know the road they're taking, they drive however fast they like, until they get near a camera. They slow down until they're out of reach and then speed up again. Also only about 1/3 actually have a camera in them, but they get ro…

In the UK we have (only a recent thing, so afaik it's not massively common yet) "average speed" cameras - they take a photo of you at two points along a road, and calculate your average speed by how long it took you to get from A to B, then ticket you for speeding if it was too quick. That prevents people from just slowing down when there's a camera coming up.

Re: Is Every Speed Limit Too Low?

#189

Post by oftenwrong » Tue, Aug 05, 2014, 1:01 PM UTC

TeMPOraL wrote: post #181

Scoundreller wrote: post #156

Earlier quoted context omitted.

It would be an easy sell if drivers (such as myself) didn't feel convinced that highway speed limits are arbitrary. 100km/h is a very unlikely number for an engineer to calculate as an upper boundary for a road. It wouldn't be a tough sell to lower speed limits on some portions, and raise it on others, even on a time-neutral but safety-positive basis, but yet, the powers that be stick to their arbitrary number.

> 100km/h is a very unlikely number for an engineer to calculate as an upper boundary for a road. I haven't seen any actual calculations used for setting speed limits, but I do remember being taught in school (on physics lessons) that if you want maximum road throughput then after factoring in safe distance (which is proportional to square of velocity) you end up with ~50km/h as a sweet spot. Even if some other facto…

A safe travelling distance can also be enforced in an automated fashion.

Re: Is Every Speed Limit Too Low?

#190

Post by saalweachter » Tue, Aug 05, 2014, 1:03 PM UTC

Spooky23 wrote: post #157

rtpg wrote: post #148

Earlier quoted context omitted.

Well, there seems to be this myth that its OK to speed 5 miles above the posted speed limit, so the speed limit is still useful. It'll just be limiting the speed to 60 instead of 55. As to whether things are enforced that way, that's a different story.

There's a lot of truth to that. Many places use 7-10 mph over as a threshold. Smaller tickets always get plead down, and cops get measured by collars or tickets. I don't think skirting the limits has much impact on behavior as the limits go up. In my personal observation, I've observed little if any difference between highway driving on the Deegan Expressway in NYC (50 mph), i95 in South Carolina (70/75) or the mass…

Is the statistic NYC posts a lie? For a few years they've had signs up claiming that 80% of pedestrians hit at 30 mph survive, while 75% of pedestrians hit at 40 mph were killed.

That seemed like a pretty good reason to have lower speed limits in pedestrian areas to me.