The trick to speed control is to set the speed limit 10-20 mph slower than you expect traffic to actually go, and never or infrequently enforce it until it exceeds +20mph. This is the M.O. for many places already.
Is Every Speed Limit Too Low?
61–70 of 214 posts
Re: Is Every Speed Limit Too Low?
#62Disclaimer: 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 sure you hear this all the time, but it's my understanding that US drivers are not nearly as well "trained" as German drivers. Anecdata, yes yes. It's trivially easy to acquire and maintain a driving permit here in the States, and it shows. (US citizen here - I don't know about German drivers, but of course the skills of Germans are legendary. The automotive media tells us all German drivers are as skilled as Wal…
There is some truth to that, we have more training: 14x 45min of theory school-style lessons and at least 12x 45min of practice with a certified driving instructor. Also, the minimum age to be driving on the road is 17, and you have to be accompanied by someone 21+ until you are 18.
The skills here are not legendary per se; the mean might be a bit better. The difference is that people seem to have more respect for other drivers and dangers on the road, creating more awareness overall.
But still, I think allowing skilled drivers to drive faster would do no harm to the population, if the faster people stick to the guidelines. For example: you do see the occasional snail moving in the left highway lane, but it won't be long until he is ushered away by some faster car with some furious flashes of the brights.
Re: Is Every Speed Limit Too Low?
#63I 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…
It's not an arbitrary premise, it's studied: “Over the years, I’ve done many follow up studies after we raise or lower a speed limit,” Megge tells us. “Almost every time, the 85th percentile speed doesn’t change, or if it does, it’s by about 2 or 3 mph.”
Had the unique experience of entering into Utah where the highway speed limit was 80mph (~ 130 km) and had no desire to drive any faster than that, it was a very comfortable speed for that road and everyone was going about the same speed so it didn't clog up or get a lot of people changing lanes to adjust.
For a long time in Nevada there were no speed limits (prior to the 55 law) and we'd drive up 395 toward Reno at 80 - 85 mph which was just fine.
It seems like you just have to believe that making a faster limit won't ratchet people to 'limit + 15' where they are when it is 65.
Re: Is Every Speed Limit Too Low?
#64Earlier quoted context omitted.
Wrote my masters thesis in transportation planning on traffic calming. Peer review or it didn't happen. Not that peer review is perfect, but a viral video with an obvious agenda doesn't do it for me.
Heh, fair enough to be sure. However the video and the associated article that I linked do in fact reference multiple official studies. Examples: - http://www.fhwa.dot.gov/publications/research/safety/97084/9... - http://www.th.gov.bc.ca/publications/eng_publications/speed_...
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 close to pure physics you'll find in transportation engineering):
From the FHWA's report:
These requests are founded on public knowledge that crash severity increases with increasing vehicle speed, because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity. Simply stated, when a vehicle is involved in a crash, the higher the vehicle speed, the greater the chance of being seriously injured or killed.
and quoted by the BC report:
A driver’s choice of speed can impose risks on other road users. Crash severity increases with increasing speeds because in a collision, the amount of kinetic energy dissipated is proportional to the square of the velocity.
Now, beyond this, there are some subtleties. Both of these reports state that crashes are more likely to occur when there is a greater delta between fast and slow roadway users. That's fine. They also talk about how speed limits are more likely to be exceeded where the roadway design encourages higher speeds. Emphatically agree.
So, now we are left with a policy question. Surely we agree that habituating people to breaking the law is bad. 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?
Normatively, for most roadways (especially those containing bicycles and pedestrians), I say we need to move more toward changing the roadway design to discourage higher speeds. On some highways, it might be appropriate to lift speed limits, though even then I'd tend to cast a cautionary gaze toward the Montana experiment that was referenced elsewhere in this thread.
Re: Is Every Speed Limit Too Low?
#65I 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 rotated every once in a while.
Actual policemen with a camera are rather rare - considering how much road we have - and they get reported to radio stations. Though they're not allowed to tell listeners where they are exactly, only which road they're on.
Re: Is Every Speed Limit Too Low?
#66Disclaimer: 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…
Yes, the main point is that I pay more attention when driving faster on a freeway. One need only take a road trip in Australia to see how ridiculous low speed limits on open roads are. 110 kmh limit with, yes, very strong enforcement in place, in a completely rural area with few cars around, no people, no pedestrians, on a long drive (it's ten hours from Melbourne to Sydney with basically nothing in between). Result…
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.
Re: Is Every Speed Limit Too Low?
#67This 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 respected them.
this, according to him, meant that even if some people were driving faster a lot of those who used to break the rules now followed them.
I'd still love to know if anyone has any more pointers to research on this and I am fairly sure someone around here knows a whole lot. ( I got some unexpected input in the other thread already.)
Re: Is Every Speed Limit Too Low?
#68This 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.
As I said, to the extent that the article made the case for combining speed limits with roadway design, I agree.
However, the quote from the Lieutenant was clearly stating that speeding was not the problem. The whole article appears to have been either crafted or embarrassingly not crafted to muddle these two questions.
Re: Is Every Speed Limit Too Low?
#69This 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…
Interesting! Of course the Dutch are also leaders in highly designed shared streets that make the hippest of the hipster urban designers in the US swoon with envy. Unless we're talking about major highway facilities (and perhaps not even then), my hunch is that we're looking at some radically different street design.
Re: Is Every Speed Limit Too Low?
#70Earlier quoted context omitted.
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 ti…
>'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.