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Do higher speed limits cause more car accidents?

Considering how many people have complained about lower speed limits, I wonder what they have to say about this article, and the assertion that “Accidents that occur at high speeds are more often fatal…”

Here is a link to the article—> http://www.slate.com/articles/news_and_politics/explainer/2012/06/texas_85_mile_per_hour_speed_limit_do_higher_speed_limits_cause_more_accidents_.html

I like the fact that the article contains links to relevant studies.

I’m originally from the Netherlands and spent a fair bit of time in Germany where people drive insane speeds by American standards. You don’t see very many accidents over there. I think it depends on discipline while driving. Germans in general drive very well, I think. To get a driver’s license there takes a bit more training and tests than it does here.
Of course, they drive lesser distances as well so it may not be an apple to apple comparison.

From my personal experience, I agree that higher speeds cause more fatalities. I also feel that higher speeds on UNDIVIDED highways cause both more accidents and and more fatalities. So the general statement about higher speeds is relative to conditions and type of highway. IMO, many 55 mph divide highways are death traps compared to 75 mph interstates. Here in snow country, driving conditions along with speed are much more important than posted speed limits alone.

I also feel that driving experience and the inability to differentiate who is allowed to drive fast allong with the condition and type of many vehicles makes it imperative to either rethink higher posted speeds or restrict them. I think RemcoW 's observations are in line with my thoughts.

The article said that the difference in speeds is the issue, and I buy that all day. You can’t control how slow people will go on the highway. I drive on I-05 every day, and even though the lanes are clear, people sill drive 50 MPH in a 65 MPH zone. Occasionally, drivers putz along even slower. I’ve driven on the interstate between San Antonio and Austin, and I find it hard to believe that anyone could sustain 85 MPH for very long.

Remember that stopping distance is directly proportional to the square of the speed. If someone is going 85 on that road, it will require twice the distance to stop as a car going 60. That means that if a car going 60 does an emergency stop, a car going 85 just behind them will hit them at 60 MPH. Dead people all over the place.

I don’t think the number of accidents increases when speed limits are raised. The severity of the accidents is likely worse. More speed means more energy and energy out of control causes more damage.

I don’t think higher speeds increase accidents. I believe habits of people like texting, eating, clustering, riding for an extended period of time next to semi’s, etc cause accidents.
I also agree with uncturbo that the higher speeds increase severity.

After all, when people text, install rebar under makeup ( : sleep, etc., it does not matter if they are traveling 40 mph or 80, something bads gonna happen.

Sure, but IMHO it boils down to the driver. Me I would be happy with 100 mph, but it is not about me, it is about every one else on the road.

They say fast drivers get in accidents, but slow drivers cause them. I agree with that. But I like to drive fast and if there was no speed limit I would cruise at 95 or so on the highway with occasional bursts of higher speed when no traffic was a factor. Obviously no one should drive fast in residential areas.

Everyone thinks they’re a better driver than the next person, myself included in a lot of cases. The main problem IMHO is the elderly and inexperienced drivers, plus anyone who is emotionally upset or distracted. And since you can do little about most of these, I grudgingly admit that speed limits are necessary on highways in the USA. But cars are a heck of a lot safer than they were even 20 years ago. I wish they’d raise the speed limit to 80 and then enforce that.

Once you are over 60 MPH, seat belts and airbags start to become ineffective. Once you are over 75 mph, they become almost useless…Steel guardrails and other obstructions tear the car to pieces. Cars that “leave the road” at speed tend to dig into the soft ground and start rolling over multiple times. The doors and other body panels are torn off and occupants are thrown from the vehicle regardless of seat belts or airbags…

Those crash tests you see depicted on TV are usually done at 45 MPH or slower…

Sorry to stay on this divided vs undivided highway kick, but the undivided 55 mph closing speed of a 110 with cars going in opposite direction by just a few feet makes cruising on the limited access, divided highway at 80 mph pale in significance. Unlimited access, bike riders, joggers and all too often UN fenced access to wild life yields more carnage per mile then ANY limited acces highway at ANY speed. Ask any one who has had to in investigate accidents.

The article skirts the issue completely. In addition, Texas highways are virtual landing strips compared to the hills and curves in other areas which make even slightly wet pavement a completely different driving driving experience. This article makes for a Texas issue alone and frankly should be limited to their statistics which would be completely different then say Hartford Connecticut. Comparibly, 80 mph given their situation does not seem excessive what so ever as long as the traffic flow shows minimal variation in speed. Heck, even 90 mph seems at times acceptable. Even then, the ability to pick up slower traffic, like the ability to pick up an armadillo from a mile away is a distinct advantage.

IMO, it’s a Texas issue, unrelated to most New England driving. Those of us who complain about lowering speed limits do so relative to our own areas. With all due respect, this article adds little to the disagreement my perception of excessive speed does to those with driving experience and statistics accumulated from the autobahn or Texas highways.

@dagosa:

...Texas highways are virtual landing strips....
Yes, in some parts of Texas they are, but Texas is a huge state, with a very diverse landscape.

It’s not the speed so much as the difference of speeds. If everyone drove at 80-85 MPH then you probably wouldn’t see many accidents. The problem lies with the 1-3% of people who insisit on driving signifcantly faster or more commonly, much slower than the the prevailing speed. When 97 out of 100 cars are traveling at say 80 MPH (no matter what the speed limit may be) the 3 people traveling at say 55 MPH are a problem, likewise the 3 people driving at 100 MPH are a problem.

just rember this simple rule stay right pass left and don’t do 45 in the left lane

I agree with FoDaddy. Flocking* birds never seem to run into each other. They just move almost as one, very gracefully. Their brain is the size of a pea!
If we only learned from that and we all agree to move within a +/- 5 mph margin of some comfortable speed (65-70?), everything will go smoothly. It is the people that zip in and out around cars or those that drive ridiculously slow on the highway that are the actual cause of accidents.
Once we all agree on basic behavior, we’ll all be flocking drivers to everyone.

After we get together on that, we’ll bring peace to the middle east and solve that pesky cold fusion problem.

(*Yes, with an ‘fl’ although it was tempting to call them something else this morning, after finding their mess on my windshield)

I lived for many years in NE where IMO the speed limits were set unreasonably low. The result. Almost no one obeys the speed limits. The speed limit on a main artery leading to the city where I worked was 55mph. The majority of traffic routinely traveled at 70+mph. The biggest hazard was the occasional driver driving 55mph limit. When I moved to the SW I was surprised to find that speed limits for similar roads were much higher and IMO more reasonable. The result. Most drivers observe the speed limits and travel about the same speed. Much safer IMO.

The article makes it pretty clear you can draw any conclusion you want from the studies. It all depends on what you are looking for. None of the studies will tell you what to do if you find the accident rate goes down but the death rate goes up. That is a public policy issue.

just rember this simple rule stay right pass left and don't do 45 in the left lane

Easy to get Germans to do it. Not so easy with us Americans. Many people figure it’s a public road, and they can drive where they want on it. Even in states with left-passing-only laws, cops don’t enforce them much, preferring to go for the more lucrative speeding and drug stops.

I’m a firm believer that yes, they do.

I’m not sure about the magnitude of the difference, however. But here are a few points and observations for why I believe this:

  • If we’re talking about roads that aren’t divided, limited access highways, you now have opposing traffic with higher closing speeds. That won’t directly cause an accident, though it gives less reaction time for any problem with the pass (ie, the other driver deviates just slightly). Most vehicles are less stable and less maneuverable at higher speeds, too.

  • For any non-limited access road, you can have traffic crossing the road. All else being equal, the cross traffic has just as much time to cross as before, but timing that crossing just became more difficult. Its easy to judge if that gap between two cars moving at 10 mph is big enough for you to shoot. It is much more difficult if they’re going 65 mph, 85 mph, etc.

  • Any time you have obstructed views in corners and turns, you have just reduced your reaction time to what lies around the bend.

  • From my experience, drivers don’t adjust their following distance properly for higher speeds. They’ll stick 15 feet off your bumper whether you’re going 30 mph or 80 mph. That is bound to cause more accidents with increased speed.

  • Let’s not forget about other factors - such as deer crossing the road. It is VERY easy to avoid them while driving 15 mph through the county park. It is MUCH harder at 55 on the freeway when they jump out from the trees. Its even harder at 85.

  • And finally, let’s consider mechanical problems. I’ve seen cars break tie rod ends going around a city street corner. Scary for them, but less likely to cause an accident and other damage. However, if that vehicle has that happen at higher speed, the likelihood of them safely coming to a stop without hitting something else or without someone hitting them would drop significantly, I would wager.

Net, I’m not sure if increasing speed limits from, say 55 to 65 or 65 to 75 cause a large increase in the number of accidents, but I’m confident it would cause SOME increase in accidents.

Personally, I question what Texas expects to gain my raising the speed limit from 80 MPH to 85 MPH. What problem would it solve? Is 80 MPH really not fast enough?

you now have opposing traffic with higher closing speeds.

True. However, we’re already closing at 110mph. If you head-on, you’re already in significant trouble.

Most vehicles are less stable and less maneuverable at higher speeds, too

Most vehicles today are at least as, if not far more, stable at 80 than vehicles in 1973 were at 55 when the national 55mph speed limit was enacted.

It is much more difficult if they're going 65 mph, 85 mph, etc

I don’t really agree with this. You go if you’re sure you can make it. If you’re not sure you can make it, and with room to spare, you don’t go. If your supposition were correct, then almost anytime someone decided to speed on a road with cross traffic, there would be a wreck.

* Any time you have obstructed views in corners and turns, you have just reduced your reaction time to what lies around the bend.

I don’t think anyone is suggesting an 80mph speed limit on the Tail of the Dragon. But if the road is straight, and doesn’t have hills, and cross streets are limited (you see a lot of these in places like Iowa and Montana) there’s no reason 80mph can’t be safe.

* From my experience, drivers don't adjust their following distance properly for higher speeds. They'll stick 15 feet off your bumper whether you're going 30 mph or 80 mph. That is bound to cause more accidents with increased speed.

This goes to driver training and traffic enforcement. If you want to talk about more stringent training and testing, and more law enforcement concentration on ticketing tailgaters, I’ll lead the charge. As it is, driver training and testing in this country is laughable. One big reason people can do 150 on the Autobahn without daily carnage is that Germany trains its drivers much better, and holds them to much higher standards. I’d be all for that here.

* Let's not forget about other factors - such as deer crossing the road. It is VERY easy to avoid them while driving 15 mph through the county park. It is MUCH harder at 55 on the freeway when they jump out from the trees. Its even harder at 85.

So don’t make the speed limit 85 in deer-prone areas.

* And finally, let's consider mechanical problems.

Again using Germany as an example, if you have a rolling crapheap, you can either fix it, or stop driving it. Drivers are expected and required to keep up with maintenance. The difference here is that a cop can watch a car spewing clouds of burning oil, bouncing like a kid on a bed because of bad shocks, and with the wheels at a 10 degree camber, and he won’t pull the guy over unless he has a busted taillight. If you want to talk about requiring that cars be roadworthy, I’ll lead that charge too.

The way I see it, the problem is not that “speed kills,” because that is patently false - if speed killed, then pilots would die shortly after takeoff. Crashing at speed kills, and crashing is something that can be significantly reduced by requiring better drivers and better-maintained cars.

This is why Germany’s deaths-per-mile-driven on the Autobahn is usually similar, and often a bit lower, than the deaths-per-mile-driven on our interstates.

Driving environment is so huge a factor in the probability of getting in an accident that no speed number can possible be applied across the board.

In the plains states, one canm drive many, many miles without encountering a hill or curve, and visability is all the way to the curve of the earth. You can see another vehicle from miles away. In NH, the roads are constantly curving and going up and down, full of broken areas and varying “crowns”, with trees, hills, rocks, and countless other obstacles limiting how far you can see the road ahead and thus how much time you have to plan.

I’m unconvinced that doing 80 on a straight level highway in the plains states increases the chances of an accident. However, doing 55 on many NH roads will get you killed.

On divided highways in particular I wholeheartedly agree with the statement that fast drivers get in accidents but slow drivers cause them, the exception obviously being extreme speeds. Try to race along at 110 mph on a NH highway and if you crash it’s a good bet that you are at fault.

What speed does in all cases is increase the change of injury.

Caddyman, your post leaves me puzzled. I’d be interested in seeing your source for the data upon which you base these statements.