Is Every Speed Limit Too Low?
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Is Every Speed Limit Too Low?
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Re: Is Every Speed Limit Too Low?
#2There's got to be a term for it, but the factors that influence how fast people drive on a road include how well it's been maintained, how congested it is, but also purely visual factors like whether there are trees or signs or buildings crowding the edges of the roads.
There's also the "They aren't serious about it" effect. Warning signs should be reserved for locations where it really would be dangerous to exceed a certain speed, either because there's an intersection just after the crest of a hill, or a reverse-banked curve, etc. So people have been trained to ignore the warnings because they're so familiar and have proven (most of the time!) to be not all that important.
Re: Is Every Speed Limit Too Low?
#3Their reasoning about the dangers of low speed limits make a lot of sense when you're looking at highways, but I don't think they'd necessarily apply to city or residential streets where there are frequent red lights, pedestrians, etc. Of course, the right thing to do there is probably to configure the roads so that people drive more slowly naturally by narrowing lanes, having trees on the side of the road, etc.
Re: Is Every Speed Limit Too Low?
#4I found myself disagreeing with the premise that highway speed limits don't influence people's driving speed. I may simply be part of the 15%, but consider the following anecdata: On I-90 in upstate NY, the "speed limit" is 65. I've gone by several state troopers at 70-75 without issue or confrontation. I don't go faster, not because traffic dictates, but I'm concerned about litigious policemen. To put it in Freakonomic terms, I'm going just slow enough that I won't get caught. If the limit was 10 mph higher, I'd drive 10 faster, as would everyone who was on the road for more than one exit (or governed semi tractors).
There is very little crowding on the stretches of highway I'm most familiar with. If the speed limit was 120, I'd probably cruise around 90 or so, assuming it wasn't rush hour. I propose that there is a diminishing impulse for travel rates as they increase, but also that on well-cleared, divided, limited-access highways, we have diminishing utility for speed limits as a regulating concept. Highway driving is the easiest driving to do. There are more variables in control than anywhere else. Why not re-evaluate the roads, not based on the 85th percentile of drivers living under the threat of litigation based on arbitrary bureaucrats, but on simple road capacity and volume?
Re: Is Every Speed Limit Too Low?
#5Their reasoning about the dangers of low speed limits make a lot of sense when you're looking at highways, but I don't think they'd necessarily apply to city or residential streets where there are frequent red lights, pedestrians, etc. Of course, the right thing to do there is probably to configure the roads so that people drive more slowly naturally by narrowing lanes, having trees on the side of the road, etc.
Or by designing roads around encouraging bicycling and pedestrian safety:
- exclusive traffic phase for pedestrians and cyclists (all automobiles receive a red light) at intersections
- protected bicycle lanes
- no right turn on red
- allow the Idaho stop
Of course, all of this is predicated on having places where people actually want to walk/bicycle.
As opposed to the typical suburban wasteland of concrete, tarmac, strip malls and exhaust fumes.
Cars kill. Sometimes even directly.
Re: Is Every Speed Limit Too Low?
#6Their reasoning about the dangers of low speed limits make a lot of sense when you're looking at highways, but I don't think they'd necessarily apply to city or residential streets where there are frequent red lights, pedestrians, etc. Of course, the right thing to do there is probably to configure the roads so that people drive more slowly naturally by narrowing lanes, having trees on the side of the road, etc.
Part of the idea behind the 85th percentile speed idea talked about in the article is that drivers understand the dangers around them and slow down accordingly. If there are a lot of pedestrians around, most drivers will slow down a lot. Not all of them, but that's why you ignore that last 15%.
The one thing the article doesn't mention though is a phenomena of traffic queuing at speed, which happens with average speed cameras. It supposedly increases the chances of collisions, because everyone is going at the same speed, not paying enough attention (because little is changing) and not maintaining enough stopping distance. I don't have citation for this unfortunately. Maybe someone else has a link to the study.
Re: Is Every Speed Limit Too Low?
#7Their reasoning about the dangers of low speed limits make a lot of sense when you're looking at highways, but I don't think they'd necessarily apply to city or residential streets where there are frequent red lights, pedestrians, etc. Of course, the right thing to do there is probably to configure the roads so that people drive more slowly naturally by narrowing lanes, having trees on the side of the road, etc.
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 comparison of the USA with Germany (where there are even roads that don't have a posted speed limit, which foreigners misunderstand for unlimited speed allowed). 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. That's even with Germany being far more populated than the USA.
So you might say, well, Americans drive more. 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. And then when you look at the statistics of automobile deaths per miles driven you get a 55% higher death rate in the USA than in Germany. There seems to be rather tenuous correlation between traffic danger and speed, at best.
The problem is horrible drivers, not speed. We should have a far more rigorous system of driving qualification and recertification. But who are we kidding, speed limits and enforcement have nothing whatsoever to do with safety.
Divest the conflict of interest between governmental coffers and speeding tickets and then you can maybe start having a case that the motivations are somehow related to safety. But that's a whole different issue called unfettered government corruption and graft.
http://en.wikipedia.org/wiki/List_of_countries_by_traffic-re...
Re: Is Every Speed Limit Too Low?
#8I found myself disagreeing with the premise that highway speed limits don't influence people's driving speed. I may simply be part of the 15%, but consider the following anecdata: On I-90 in upstate NY, the "speed limit" is 65. I've gone by several state troopers at 70-75 without issue or confrontation. I don't go faster, not because traffic dictates, but I'm concerned about litigious policemen. To put it in Freakono…
You do raise a good point. I know that, when I started driving, my dad taught me a neat trick: drive 8.5 mph over the speed limit, and you'll never get pulled over. That's (supposedly) because a ticket for anything less than 10mph is simply not worth it for the cops. If you go any more than 8.5mph over, though, you might accidentally cross that 10mph mark, and if a cop's around he'll get you.
And, sure enough, any ticket I've ever gotten is because I was going over 10mph faster than the speed limit.
Re: Is Every Speed Limit Too Low?
#9Their reasoning about the dangers of low speed limits make a lot of sense when you're looking at highways, but I don't think they'd necessarily apply to city or residential streets where there are frequent red lights, pedestrians, etc. Of course, the right thing to do there is probably to configure the roads so that people drive more slowly naturally by narrowing lanes, having trees on the side of the road, etc.
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…
[deleted]
Re: Is Every Speed Limit Too Low?
#10There's got to be a term for it, but the factors that influence how fast people drive on a road include how well it's been maintained, how congested it is, but also purely visual factors like whether there are trees or signs or buildings crowding the edges of the roads. There's also the "They aren't serious about it" effect. Warning signs should be reserved for locations where it really would be dangerous to exceed a…
"Traffic calming" is the term used for the stuff you described that causes drivers to instinctively slow down. Curb extensions at crosswalks and narrow lanes seem to be the most effective measures, in my personal experience.