Using the article's logic, why have speed limits on country roads at all?
Is Every Speed Limit Too Low?
171–180 of 214 posts
Re: Is Every Speed Limit Too Low?
#172This 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…
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)
Re: Is Every Speed Limit Too Low?
#173Earlier quoted context omitted.
Respectfully, you didn't read the rest of the abstract to the article you cite, and the next few sentences support what the article says: >Other studies looked at speed dispersion and found evidence that this is also an important factor in determining crash rate. Larger differences in speed between vehicles are related to a higher crash rate. Without exception, a vehicle that moved (much) faster than other traffic ar…
Respectfully, I did, and you're failing to acknowledge what I wrote in my initial posting. > it is saying that speed differential is more dangerous than speed. No it's not, the article is saying that a delta in speed is a factor in crash frequency. (And no, I didn't copy paste the whole abstract, because I was posting the part of the abstract germane to the quote I cited from the original article.) > This is a horrib…
As the article states, the 85th percentile rule is as old as the hills, and the principle about speed differential is as well. All the data I've ever seen would appear to support it. Do you have any theories as to why states with higher speed limits (or in Montana's case, no speed limits) don't have terribly different worse outcomes from those that have lower ones?
Re: Is Every Speed Limit Too Low?
#174Earlier quoted context omitted.
>At least I'll get to sleep in for 3.5 more minutes. Come on, that's not a fair argument. The effects are obviously much bigger than one guy saving 3.5 minutes. To get closer to the meat: If your calculation always outputs numbers that make slower traffic look better, no matter what the starting speed is, then your methodology is wrong. Your method here would make 15mph look better than speeds 20mph or faster, despit…
actually my argument is based more around 60 mph average speed because that's more or less the average speed on highways and people spend a decent amount of time driving on highways and the like. Also, the increased fatality rates were concerning a rise from 60 to 70mph. Obviously if we're going from 15 to 20 the numbers change. But at the same time if people were on average driving around at 15mph on average car acc…
>actually with lower speed limits you would gain more time
Right, not sure why you have 'actually' there because that was my point. When you picked 60 vs. 70 you were picking the speeds most likely to favor not going faster.
>the speeding people commit usually doesn't earn them much more time, but disproportionately endanger themselves and those around them
It's the 'disproportionately' that's at argument. A tiny-per-person cost for a noble purpose seems like an obvious choice, but when you repeat the action a billion times over it gets more complicated.
Re: Is Every Speed Limit Too Low?
#175Earlier quoted context omitted.
The tradeoff for speeding is stupidly small. Average US worker spends 25 minutes on a one-way trip to work. Lets assume an average speed of 60mph (hint: it's slower). If you went at 70 instead of 60, then you'll save a whole 3.5 minutes. Here( http://webcache.googleusercontent.com/search?q=cache:jWbI1mK... ) is a link to a NHTSA presentation on speed limit changes and its effects on crashes. Notably, when states were…
You still haven't shown that the increased risk of danger outweighs the aggregate time savings. It's a big consideration when looking at things like, the value of screening for unlikely outcomes. 3.5 minutes/trip saved * 2 trips/day * 200 working days per year (probably more) = 1400 minutes saved per year per person. working-age population of US (2012) = 243 million. Employment-to-population_ratio = 67%, so 162 milli…
so, 2,700 additional lifespans of time saved in trade for 10,000 people killed, let's pretend each of them was halfway through their lifespan (40) so we lost 5,000 lifespans of time, or net loss of 2,300 lifespans. Sounds like it's not worth the time savings.
Re: Is Every Speed Limit Too Low?
#176I'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 posted speed limit be the speed at which no one drives except when the police are around.
Re: Is Every Speed Limit Too Low?
#177An interesting rhetoritcal question is what will be a suitable speed limit when we have roads that are 100% autonomous vehicles?
Re: Is Every Speed Limit Too Low?
#178Disclaimer: 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…
>>My personal theory is that this is one of the main reasons why German drivers are so aggressive.
AS a person who drives through Germany frequently I am yet to see an aggressive driver on the Autobahn.
My point? Anecdotes don't prove anything. One person says that Germans are aggressive, another says they aren't. We need hard data instead.
Re: Is Every Speed Limit Too Low?
#179Earlier quoted context omitted.
Exactly -- sure, you can still hide behind a truck and go 100 km/h all the time -- but most cars efficiency sweet spot is around 130 km/h, and driving at that speed leads to more dynamic, occasionally passing trucks, etc.
What is an "efficency sweet spot"? When I consistently drive at the speed limit (in the Netherlands, 120km/h) I have to fill up every 4 working days. When I consistently drive 100 km/h I only have to fill up every 5 working days. Takes 20% longer but the tank also lasts 20% longer.
Depends on the car. If you have a tiny engine, then it will use large amounts of fuel at high speeds. If you have a large engine, it will use less. My personal experience:
Peugeot Partner 2.0 HDi - 6-7l/100km when driving in city traffic, 12-13l/100km when driving at 140km/h,
Land Rover Discovery 3 4.4L V8 - 15-16l/100km when driving in city traffic, 9-10l/100km when driving at 140km/h.
Basically your engine should stay below 3000rpm - if you have to keep it at 4000rpm just to maintain a certain speed then it's too much for the engine and it's not being efficient.
Re: Is Every Speed Limit Too Low?
#180Speed does not cause accidents. Bad driving does.
The two are sometimes, but not always, linked.
We should stop focusing on policing speed and start policing bad driving.