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How To Build Roads To Control How Fast You Drive
An anonymous reader writes "They're the holy grail of transportation engineering: streets and highways specifically designed to encourage automobilists to drive less quickly, reducing the rates of passenger fatalities and generally encouraging a safer urban environment. And now new research shows that, if built right, they just might work. A new study out of the University of Connecticut suggests that minor reductions in vehicle speed are possible through changes in the street environment. Through the use of roadside parking, tighter building setbacks, and more commercial land uses, road designers can make drivers subconsciously drive more slowly." All of that is gonna work a lot better than my strategy of placing car-sized holes covered with twigs and branches randomly every half mile or so down the interstates.
Good grief. From TFA:
And:
Who would have thought that by reducing a driver's visibility, the driver would go slower to give themselves time to react to surprises? You? You in the back? Are you some kind of smartass? The Connecticut Department of Transportation studied this for four years. There's no way you could have arrived at the same conclusion so quickly!
This study was useful in determining how much people slowed down -- quantifying it at about 10% -- but sweeping on to claims like, "reducing the rates of passenger fatalities and generally encouraging a safer urban environment" is silly. Streets packed with parked cars, pedestrians, nearby buildings, et. al. are generally more dangerous precisely because clear lines-of-sight are cut off. Sane drivers know this, reduce their speed, and then -- making wild hand-waving guesses, here -- wind up with about the same overall level of "dangerousness" as when driving on uncluttered roadways.
1) You can make the road look more dangerous, e.g. with optical illusions to make it look narrower
2) You can make the road actually and obviously more dangerous, e.g. reducing sight lines and adding on-street parking
Number 2 works, but it doesn't increase safety. Number 1 works... for a while. My concern with #1 is that drivers will realize they are being fooled, and start speeding up again. That's OK, except they may then interpret the real situation that the illusion was imitating as an illusion, and fail to take it into account, resulting in a net decrease in safety.
All of that is gonna work a lot better than my strategy of placing car sized holes covered with twigs and branches randomly every half mile or so down the interstates. Sadly, your strategy seems to have been widely adopted across the UK recently. I preferred the speed cameras - at least they didn't destroy your suspension ..
Studies show that drivers adjust to the speed at which they feel safe, regardless of posted speed. So the only way to make them go slower is to make the road inherently *less* safe.
Also, similar studies show that driving about 5-10 mph faster than posted is actually about the safest speed you can go.
http://www.motorists.org/speedlimits/
There's also the argument that restricting the ability to drive quickly kills, as you slow emergency response vehicles as well. http://www.bromleytransport.org.uk/Ambulance_delays.htm
All in all, one of the dumbest proposals I've ever heard. It seems that one of the easiest mistakes to make as an organization is to try to optimize for one contributing factor (speed) while ignoring the point of restricting that factor in the first place (reducing accidents).
Most roads are already quite curvy in Europe and I'm pretty sure new roads are constructed in the same manner to encourage lower driving speeds. Straight lines make people want to speed, lots of turns and twists make people want to break, so maybe making all your roads as straight as possible and thus creating grid-like layouts isn't such a good idea after all.
A side effect of less straight roads could also be a decline in traffic jams, because curved lines are longer than straight ones and thus can hold more cars.
Pretty good is actually pretty bad.
speed bumps also greatly slow down emergency vehicles. If you have ever been in an ambulance going over speed bumps you will curse the name of whoever came up with such a painful idea
the preceding post was not spell checked... suck it.
In Portugal I saw a cute system - if you pass a sensor driving faster than the speed limit, then a traffic signal 200yards/metres down the road turns red for 10 seconds, making you (and again anyone behind you) stop.
The psychology behind these systems is interesting - both rely on shaming you in front of other drivers. The Portugese system goes further and makes other drivers angry with you for speeding.
As a former employee of an international road transportation company, we studied the exact same thing.
Interesting fact. When someone is driving in a place they don't know, they drive slower. You can duplicate the effect by making changes to a known environment, like this study does by adding cars to the roadside. Second interesting fact? Once the changes become 'known', speeds return to what they were previously. I notice this part is somehow absent in the claims that "the lower speeds make things safer."
If I was from the University of Connecticut, I'd be embarrassed to be releasing this study.
First of all, "holy grail of transportation engineering"?? Bullshit. The goal of transportation engineering should be to achieve the best balance of maximized capacity, efficiency, and safety. You can always make roads safer by slowing things down - until you try to make them safer by causing congestion.. and the congestion causes frustrated and aggressive driving. The study basically says to throw more shit in the way of drivers to slow things down.. That's because it's creating an unsafe environment.. and drivers naturally try to compensate for it.
Here in Florida, the transportation engineers have decided that old people react slower. Therefore, all traffic lights change slower.. So that causes inattentive driving since people can be waiting as much as 5 minutes between lights. Then, people are very slow to start proceeding through the intersection once lights turn green - partly because desperate drivers run all the yellow lights because they have to wait another 5 minutes between lights. My argument would be that traffic rules should not change to accomodate for people unable to follow the rules. Chicago's lights change quickly at an intersection..
Also, our political wanker of a governor (Charlie Christ) decided he did not like the 'move over law' because he said it promoted speeding. So, people are free to sit in the left lane of major highways going under the speed limit while others try to get around them. Florida interstates are a clusterfuck.. Nobody moves over.. So you have a clump of cars bumper to bumper for a mile.. and then a mile of highway that hardly has anyone on it.. I would argue it would be safer to have an actual passing lane and allow people to spread out.
Cars today have more horsepower, more traction, better safety, and more braking power than cars 20-30 years ago.. Yet, our speed limits have decreased.. Why?
Traffic is an absolute mess.. and the idea that 'slower is safer' is contributing to that mess.
--- We need more Ron Paul!
If you're not passing, you shouldn't be in the left lane, period. I don't care if you're doing 50 or 80 MPH, the left lane is for passing! It's people like you that fuck up good traffic flow.
But the fact is, you are making the roads more dangerous! How can this be a good thing?
Because drivers are more careful, and rarely careless, when conditions are dangerous. People being careless is usually what kills.
Alaska sees dangerous, icy roads 2/3 of the year, yet our over-all accident and death rate is lower than the national average. Shouldn't it be the case that the nice, grippy streets of the lower 48 would be much safer?
We also tend to drive individually and do less carpooling and the like because destinations are so far apart. So again, dangerous roads seem on the surface to mean people drive more carefully, for a net reduction in accidents and loss of life.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller