Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Is Every Speed Limit Too Low?

priceonomics.com

Post reply on HN
Print view View original

41–50 of 214 posts

Re: Is Every Speed Limit Too Low?

#41

Post by mwfunk »

I've lived in the US all my life, with my excessive number of years split between Michigan, North Carolina, and northern and southern California, and in all of those places the proper range of speeds was anywhere from the posted speed limit to a hair under 10 MPH over the posted speed limit (I prefer the latter :). Go slower than that and you start blocking traffic, go faster than that and you might get a ticket.

This is when driving on highways and major roads, at least.

I vividly remember the days of 55 MPH speed limits in the US, and it was pretty much the same then (a hair under 10 over was the optimal speed, but 10 over was a lower speed back then).

Anecdotal experience and all, but at least for me and other drivers that I've observed or talked to about it, just because people tend to go over the limit doesn't mean that the limit has no effect.

This is all fine by me. I only mention it because this is exactly the kind of topic overly logical people (and/or inexperienced drivers) tend to get bent out of shape about. Just because the speed limit isn't strictly enforced doesn't mean it's useless, and just because a cop could theoretically take advantage of people's behavior and give a bunch of tickets to people for going 5 over doesn't mean that it's a conspiracy by the police.

Re: Is Every Speed Limit Too Low?

#42

Post by colanderman »

streptomycin wrote: post #37
colanderman wrote: post #11

Earlier quoted context omitted.

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.”

And it's apparently controversial: Just as Megge can point to the results on hundreds or thousands of roads which have become more safe or equally safe when the speed limit increased, other researchers looking at data sets of speed limit changes have come to the opposite conclusion and advise that raising speed limits comes with the price of thousands of roadway fatalities. Although the article seems to support Megge…

The speed limit drops arbitrarily from 65 to 55 from MA-146 to RI-146 at the state border. Risk of a ticket aside, 80 is fine on either side of that invisible line (long straight flat highway with trees on either side).

Re: Is Every Speed Limit Too Low?

#43

Post by peatmoss »

cheald wrote: post #38

The data from Montana always struck me as interesting. It's not an awful lot of data presented in this report [1], but there was a substantial increase in traffic fatalities when Montana shifted from "Reasonable and Prudent" speed limits to posted-and-enforced speed limits. I then found this report [2] which indicates that yearly fatalities are approximately double of what they were in the late 90s (and is now around…

I've always loved this example. I lived in MT pre, during, and after this experiment. We went from:

- 65 Mph

- "Reasonable and prudent" daytime speed

- 75 Mph daytime speed

During the reasonable and prudent period, I think many people still had an internal model of 65 Mph. Certainly many people did drive faster. In my younger days, friends and I would find straight, empty sections of highway to flirt with death. But... many many people still set their cruise control to 65.

Case in point, my parents and the parents of many of my friends were careful to clarify that "reasonable and prudent means 65 mph, or you will have your driving privileges revoked." I was out from under the parents' roof by the time things went to 75, but I know my own highway averages went up with the codification of 75 mph.

Re: Is Every Speed Limit Too Low?

#44

Post by cfstras »

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 there are narrow curves, unclear conditions etc. In my experience, this system works wonderfully: when the road is good, you can drive as fast as you like, so people are more concious about paying attention to the road and their rear mirrors, especially when hogging up the left lane.

I acknowledge that completely overtaking this system would be impossible for the US, simply because the roads are not up to it and the driving tests are not rigorous enough, but I think Germany serves as a fine example that there would be no harm in raising the speed limits a few notches.

Re: Is Every Speed Limit Too Low?

#45

Post by mwfunk »

incision wrote: post #24
mcdougle wrote: post #8

Earlier 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…

I'm also in the "drive a little under 10 over" camp, and I totally accept that once every 10 years (or whenever), I'm going to be in the wrong place at the wrong time and get a ticket for it. I'm OK with that. It's not fair, but it's well below the bar of meaningful injustice for me to really care about it all that much.

Re: Is Every Speed Limit Too Low?

#46

Post by 3pt14159 »

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 speed limit can be safely raised to at least 130km/h for most highways that are 100km/h.

One interesting thing I observed while driving to university was that there was this one section of highway that was marked at 60km/h, but everybody drove around 95km/h. Every now and then there would be a cop that would give out a bunch of tickets, but it didn't seem to change the speed people went.

Well it turned out that the person that ordered the sign had a dyslexic moment, and the speed limit was later changed to 90km/h. What was interesting was that the design of highway (the guards, the lane width, the shoulder, the banking of the ramps) were all cues for drivers and they drove the actual intended speed without regard to the maximum speed sign.

I think that's neat.

Re: Is Every Speed Limit Too Low?

#47

Post by cheald »

peatmoss wrote: post #43
cheald wrote: post #38

The data from Montana always struck me as interesting. It's not an awful lot of data presented in this report [1], but there was a substantial increase in traffic fatalities when Montana shifted from "Reasonable and Prudent" speed limits to posted-and-enforced speed limits. I then found this report [2] which indicates that yearly fatalities are approximately double of what they were in the late 90s (and is now around…

I've always loved this example. I lived in MT pre, during, and after this experiment. We went from: - 65 Mph - "Reasonable and prudent" daytime speed - 75 Mph daytime speed During the reasonable and prudent period, I think many people still had an internal model of 65 Mph. Certainly many people did drive faster. In my younger days, friends and I would find straight, empty sections of highway to flirt with death. But.…

Very interesting. How well do you think that 65 MPH internalized limit (during R&P) mapped to the 85/15% split as described in the original article?

Do you have any other insights into other factors that might have contributed to the change in fatalities, or do you think it was just as simple as "people are driving 10 MPH faster on average", with correlated increases in fatality rates?

Re: Is Every Speed Limit Too Low?

#48

Post by DanBC »

tux1968 wrote: post #30
elinchrome wrote: post #25

Earlier quoted context omitted.

That video only gained traction in social media because it is telling people want they want to hear. It's always important to filter everything you read through "do I want to believe the thesis/conclusion of this?" Because a lot of people throw critical thinking out the window when they want to believe something.

That's not a refutation of the facts presented in the video though. There seem to be an equal number of people who support the status quo and don't want to look at facts that challenge what they want to hear. The facts should speak for themselves regardless of what each of us wants.

> The facts should speak for themselves regardless of what each of us wants.

But when I'm looking for facts I should prefer well constructed research, and not a documentary.

Re: Is Every Speed Limit Too Low?

#49

Post by BrainInAJar »

tux1968 wrote: post #18
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…

There is conflicting evidence on the matter. A local (Vancouver) video[1] circulating here had some strong arguments that our speed limits are kept needlessly low. If you're interested in such things, it's a well done video and worth the 15 minutes it takes to watch. [1] http://www.vancitybuzz.com/2013/09/speed-does-not-kill-vanco...

Frankly the conclusions of that video are "cars are safer, so we can drive faster" which totally glosses over the fact that cars are safer and fatalities are down as a result. Raising the speed limit raises the fatality rate back up to 1950's level and that point just isn't made.

Ultimately, how many deaths are acceptable for people to get to work 5 minutes earlier?

Re: Is Every Speed Limit Too Low?

#50

Post by Cakez0r »

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 think it would work to just make the inside lane unrestricted and only have speed limits on the outer lanes. That way, slow and fast drivers aren't endangering each other because they're in completely separate streams of traffic.
Post reply on HN