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Homemade Speed Trap Made By Former UVA CS Professor (cvilletomorrow.org)
An anonymous reader writes: Irritated by speeders in his neighborhood and frustrated with the City of Charlottesville's inability or unwillingness to enforce the speed limit, a former professor in the Computer Science department of the University of Virginia created a program in openCV to track vehicle speed on his residential neighborhood street: "You'll find that almost 85 percent of the cars going by are violators [of the neighborhood's 25mph limit]". This includes a city bus doing 34mph.
Authorities all over the world know that people will always go a little bit over the speed limit and hence set the limits accordingly. I know this isn't what the road safety warriors want to hear but its the truth - if they want vehicles doing around 35 authorities will set the actual limit to 30 and so on.
There is also an unwritten "grace" that is given in many areas, where you don't ticket someone until they go 10 mph above the speed limit. To get a ticket for going 34 mph in a 25 mph zone usually means you angered a cop, you were doing it in bad weather or at some other time when it was unsafe, or you wandered into a local town's legal extortion racket--excuse me, speed trap.
It is constitutionally questionable because of vagueness and due process, but it's still how driving works in a good part of the United States.
That does not mean anything if we do not know what happened or the layout of the street. Perhaps that car was speeding, but by how much? Perhaps the kid was jumping in front of the car and would have been injured anyway.
What happens in Europe is that they start making the streets in such a way that they are automatically so that you drive a lower speed. Especially in neighbourhoods where people live.
A lot of curves in the streets by placing objects in the streets., making the road more curvy and what not.
That means that the average speed will go down a lot. They just change the natural flow of traffic. and people adapt to that. Downside is that is is more expensive than placing some traffic signs and you can not generate extra income from tickets.
Don't fight for your country, if your country does not fight for you.
There is no necessity for you to drive fast around residential areas, you want to go fast, hit a highway or a racetrack or quit whinging, FML.
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The context was *a residential street*. Stop generalizing something which was very obviously not meant to be general, that's just intellectually dishonest. Alternatively you're suggesting that you're too stupid to realize that.
> exponentially
Nope. Kinetic energy is proportional to the square of the speed v:
ke ~ v^2
"Exponentially" means ke ~ C^v for some constant C, which it isn't.
Those who set that speed limit are acting in reckless disregard for the safety of the public. As is that CS professor--and he should know better!
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The other main roads feeding into downtown from US 250 are High to the east and Park and McIntire to the west. All three are heavily congested for various reasons. They link to other busy roads, have shopping and commercial areas, etc
I think the solution is for the city to bite the bullet and install speed bumps. It will not be a popular measure, but that is because people want to speed through there to get into or out of the downtown area. Too bad, just plan a little further ahead.
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"You'll find that almost 85 percent of the cars going by are violators"
Then your speed limit is set too low, unless there is some compelling reason for it to be that low speed limits should be set by the average traffic speed (within reason). I think my state even has a law to that effect.
I don't disagree with your point, but you're conflating a bunch of numbers which aren't really comparable.
1) Motor vehicle fatality rate doesn't tell you much about pedestrian fatality rate.
2) Driving distances area greater n the U.S. so those billion kilometers driven are not comparable. Dividing the fatalities per 100,000 inhabitants by fatalities per billion km yields 8100 km/inhabitant per year in the UK, versus 14,900 km/inhabitant per year in the U.S. So the average American travels 84% further each year than the average UK citizen. Most likely, a greater percentage of those U.S. miles are at higher speeds on highways where accidents are more likely to be fatal.
The problem at speeds higher than about 50 mph is physics. Given how bodies strapped inside a car react in a crash, 50 mph is about the point where internal organs and blood vessels start tearing apart from their own momentum in a crash. At 100 mph, accidents are almost always fatal for the same reason (energy that goes into tearing up your internal organs is 4x more than at 50 mph). So a disproportionate number of traffic fatalities come from these higher speed accidents. In other words, a single stat like fatalities per billion passenger km doesn't give you the complete picture. You need to control for traffic speed distribution within those billion km first just determine if there's any blame left over to be assigned to other factors like car quality, driver certification, road design, car design, etc.