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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.
If everybody is speeding, maybe the speed limit is too low.
Add a link to the summary.
How did this submission get through review? There's no link to the source article.
Slashdot's accepting citations from anonymous sources with no supporting evidence now?
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.
A 25 mph speed limit is unrealistic on any public road I've ever seen, with the exception of roads made of cobblestone. It's difficult to drive a modern vehicle that slowly--it takes concentration on your speed that frankly makes you have much less attention to pay to obstacles and hazards... like children.
If you have a 25 mph speed limit, it means that the street should not be a public street at all--the most common case is a school speed limit where they are requiring people to drive slowly because of the risk to kids. That's fine, except that when they do that it should either be the driveway for a school or it should be pretty much constant rumble strips or some other physical indicator that makes it problematic to go more than 25 mph.
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.
http://www.nbc29.com/story/311...
At least in California, other than the absolute maximum, and things like school zones, roads have to be surveyed periodically, and the speed limits must reflect the prevailing speed. If it is 85% near some higher number, including mass transit, then the limit is too low.
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Cute to use OpenCV for this, but some loops in the road could do the same thing. Over here there are signs that light up with your speed, and a frowney if you're going over the limit, a smiley otherwise. This sort of immediate feedback by signpost at least has the virtues of not being a stealth tax nor taking weeks or worse to tell you that you were speeding once, somewhere.
Look, I get that the link-in-the-header thing is different. But it's clearly visible, and it's been this way for four months now. It's tiring seeing these modded-up side discussions asking the same damn question in every other post.
Like many people, I'm disappointed in Slashdot's continuing downward slide (I don't even bother logging in anymore). But what's even sadder is the apparent downward slide in the intelligence of the readership.
Link to original article, name of the professor please.
Last summer I wrote a python opencv program for a Raspberry Pi computer and Pi camera module. This monitors in real time. It has a lower fps due the hardware capability but does work Ok when calibrated for the distance. Here is my YouTube video https://youtu.be/eRi50BbJUro github repo is here https://github.com/pageauc/mot.... This was just done for fun after reading a forum article on the subject.
Take some discarded automotive parts (coil spring, shock absorber) and fine steel cable (the original reputedly used piano wire) and run it across the road under tension a few inches above the pavement. Go over it slowly (with the speed set by the shock absorber) and you never notice it's there. Go too fast and it slices the tire right off of the rim.
Lacking <sarcasm> tags,
I consider this the electronic form of a homemade sign. Occasionally I put up messages like "slow down"
Well there is a little problem with the abbreviation of the University of Virginia (UVA) that is the same as the University of Amsterdam ( Dutch: Universiteit Van Amsterdam) UVA. In addition, i cannot see where the extra A comes from in the Virginia case .
Changing the abbreviation to UV would be a better option because Virginia University (VU) is all ready taken by the other university in Amsterdam, the Vrije Universiteit.
http://www.nbc29.com/story/31111453/charlottesville-man-researches-speeding-on-locust-ave
You can also use radar for measuring the speed. It may be more reliable and there are no problems with obtaining a permit for using a camera that sees the public road. For example: http://www.aliexpress.com/item//32280900665.html
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.
Several years ago, it was decided to standardize the abbreviations for the various states in the USofA. I presume that however it was decided, it was partly for readability. Way back when, an envelope might have "California", "Calif." (quite common), or "Cal", or whatever, making it difficult to quickly route mail.
VirginiA is VA, VermonT is VT, for example, but that pattern is not universal, as CAlifornia, ORegon, and WAshington are CA, OR, and WA, respectively.
If only the initial letter of the state is used in an abbreviation, the UV, could be University of Virginia, University of Vermont, or UltraViolet, so sometimes the longer form is used.
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!
"My opinions are my own, and I've got *lots* of them!"
In my city, we've had a trend lately of pedestrians being wiped out by cars. Most of the occurrences have been on major roads where there are 3 or 4 lanes in each direction and there are marked crosswalks in certain areas. Of course the pedestrians who have been hit were not crossing at the crosswalks. In one instance, a pedestrian was hit by 3 separate cars. Each time the local news reports about a new incident, they always make sure to throw in that 'the police are investigating who was at fault'.
Therein lies the problem. If you think that you should be able to freely walk into the road where there are cars travelling, you are part of the fucking problem. Changing the speed limits to accommodate your particular idiocy, alarmism and lack of personal responsibility will NEVER solve the problem. What solves this problem is having the pedestrians cross at the marked crosswalks (there are shittons of them, I know from experience because I have to stop at about 8 of them in a stretch of 2 miles of my commute).
PSA for the idiot parents reading this article: your kids are not special and vehicles will still splatter them all over the roadway. The problem isn't the vehicles, the problem is your kid walked into the roadway because their parents did not a) supervise them closely when crossing the street while young AND b) instill in them an understanding and appreciation of using marked crosswalks in order to not walk randomly into the road in front of cars.
My impression is that speed traps are called speed traps because something negative (ie get a ticket) happens if they catch you speeding.
This is a simple camera monitor that tracks speed, but does not result in adverse effects to the driver. How is this a speed trap? Now, if it reported offenders to the police who then wrote tickets...
"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.
Which is to say, don't take a Corvair if you need to go to Mars.
Maximum line of sight. Inclination, curve, drainage, presence of sidewalk, distance to intersection, distance to driveway, populaton of children, proximity to school, width, apparent width.
Then setup a traffic cone at various detail points in the road and measure the distance to the cone to make cars stop. You just need a cone, adjustable speed limit indicator, and a tape measure.
On my way to Canal Winchester on OH-674, I’d pass through a small section of Lithopolis, where the speed limit inexplicably drops to 45mph. It’s a well-known speed trap, for the locals, so the village makes(or made) money mostly from visitors. One time, an Ohio state legislator was caught in that speed trap, and there was a bit of a smack-down that ensued. But that wasn’t the beginning of the end of Lithopolis. That started when they closed the only interesting thing in the whole village, which was the Wagnalls memorial library.
Real question is, where does one get the source code?
The project he's working on now is a Raspberry PI that automatically shouts "Get off my lawn!" whenever it detects someone under 18 encroaching on his property.
Google streetview of location in video.
Honestly those driving sight lines look pretty good to me.
But if speeding is truly an issue, then the squirrel up there on the electric line has the right idea. (see link)
Seriously, this guy is a complete asshole. Fuck him.
If he goes to the PD and files a complaint with the recorded evidence the PD has no choice other than writing a ticket for every violation. It is handy for bicyclists to know this as with a cam mounted on the handlebars, one can get the plate number of every car that tries to pass you in the same lane or in a no passing zone.
I pass by three Government Schools on the way to work.
If I run late, I enter the Twilight Zone, er, the School Zone with reduced speed limits.
I have noticed that on any given day, the majority of the speeder are Mothers trying to get their children to school on time!
Keeping an informal tally for years, it has proven that 80% or more of speeders in School Zones are Mothers.
So much for the myth that "women care more than men".
University of Amsterdam didn't take that name until 1961. The University of Virginia was founded and named in the early 1800s. If it bothers you, petition University of Amsterdam to change their name (again).
There are things I love about this town, and things I despise; and this sort of sanctimonious bullshit ranks high on the latter.
I actually hope someone gets killed doing that. You have absolutely *no* idea why any person at any given moment is driving in a particular manner. Could be they're just late, could be a life-threatening medical emergency. What gives *you* the right to presume anything and then try to impose your presumption onto anyone else?
Seriously, that's the worst sort of selfish assholery. And while I might not shoot you dead myself for deliberately impeding my way, if such a case came before me as a juror, it's unlikely I'd convict someone else for doing it.
/. used to be populated with *actual* nerds. In today's microwave generation of BBT-watching wannabes, kids think they can adopt nerd culture by simply wearing ironic vintage shirts and chunky eyeglasses. Heaven forbid they might have to actually *understand* mathematics and physics.
I'd like to see a histogram of the speeds, just out of curiosity. The article (side note: why not link in the description?) states 63% of the cars were speeding, but are we talking about 5 mph in excess, or 10+? Additional statistics would be very useful in this case.
Amen, brotha.
Not sure why this is news. In ECCV95 (European Conference on Computer Vision) there were two separate papers published on exactly how to do this with to different methods in realtime with what then was high end but non-specialized computer hardware. The fact that somebody chose to do this twenty years later really seems to not be newsworthy.
Fucking hoo.
It really should be. He apparently codes in a language called "OpenCV"... I've only heard of a package called that. Anyway, it'd be good to have the source reviewed. It'd be easy to have a coding error that judges everyone as speeding.
-- these are only opinions and they might not be mine.
Obviously the speed limit is set too low.
I'm lucky enough to live in an area now where speed-limits are sane. The vast majority of side-roads, even residential ones are 35, not 25, for example, with exceptions only made in places where it really makes sense (school-zones). As a result, the majority of time I'm able to drive at a comfortable speed and don't get tickets. I used to get tickets frequently when living in other areas because the speed limits were simply set far too low. Much lower than is needed for actual safety, IHMO the speed limits in those areas are carefully chosen to make them uncomfortably slow and help generate ticket revenue. The difference has to do with $$$ not safety. If we collectively cared about safety on the roads we would properly train drivers, have "texting cameras" rather than speed cameras, etc... Instead we get terrible, distracted, hopelessly dangerous drivers and police departments with extra cash earned off the back of the tax-payers.
Did he not want to use Radar because people have detectors?
http://www.cvilletomorrow.org/...
speed traps are called "safety corridors".
Seems a little drastic to reduce the speed limit to zero, which is what you are effectively saying.
85% indicates to me that it's not the 85% of people that need to change, but the speed limit that needs to be raised. But that's just logic speaking.
Or it might just be that the average person in that area drives at an unsafe speed. This isn't a freeway.
Frankly, around here exceed the limit in large quantities all the time. Often they do so regardless of road conditions or weather. In most cases, they still arrive home. However every now and them somebody will hit that nice skiff of snow or black ice and "oops" - perhaps doing 110kph in a 90zone with icy roads ISN'T a good idea - now you have an accident. Even better, since the average person is already driving at unsafe speeds for the conditions, everyone else who suddenly has to avoid the fishtailing pickup also gets to experience the joys of winter acrobatics on ice, resulting in a multi-car pile-up.
Similarly, we have big issues with people passing school-buses that are unloading kids. Apparently the huge, flashing stop sign doesn't mean much to most people. Just because your average person doesn't have the intelligence to drive safely, should we just say "screw it, let's let everyone pass the stopped bus and speed on through crosswalks!"
In this case, it's a residential street. The "oops" might happen with weather, or it could be a kid crossing the street, a stray animal that somebody swerves to avoid and loses control, whatever. Sure, in most cases that won't happen, but in the other cases you could probably have avoided hitting that kid by DRIVING THE F***ING LIMIT.
Many people say that the problem is the speed limit. It may be better to look at this from the other side: If, for proper safety of the neighborhood, the cars should only be going 25 mph, then the roads should be redesigned such that cars can only go 25 mph.
This can be done several ways:
- speed bumps
- adding islands to intersections that must be driven around
- extending curbs into the street to make straight streets curvy
- blocking off some streets (or making some parts one-way)
- etc.
As required by law, speed limit is set to the 85th percentile of the operating speed on that road. Looks like that speed sign needs to be changed.
If you hit someone younger than say 13 while driving more than 15 miles above the speed limit in a Residental Area then you get charged with "Attempted Vehicular Homicide" (with any possible racial factors as riders).
Hit a Not Your Race Kid and you go "UpState" for 20-30 maybe then they would get the message
If everyone is going faster than the speed limit, and the place isn't a bloodbath, then the speed limit is wrong, not the people.
Speed Limits are *safety* rules. If you can be perfectly safe going twice the speed limit, then the speed limit is probably incorrect.
Tell the professor to go solve a problem that needs solving...
https://www.ibiblio.org/rdu/sl-irrel.html
One wonders if this same professor is making sure his dalliances with the throttle are censored out. It would be rich if this idiot forces the town to place a speedcam and he became one of its earliest victims.
Would be interesting to hide a GPS speed reporter on his car for a month and see how he drives through everyone else's neibourhoods.
Website Just Down For Me? Find out
Great Job. You deserve more recognition.
Are you using the Pi cam or are you using a USB webcam?
Thanks for sharing! Stay warm.
There is well established precedent on how to reduce speeds on highly used residential roads. It's called "Traffic Calming". Essentially, you redesign the road so that it is narrower, curvier and gives better access to pedestrians and bikers. The basics of Traffic Calming can be found here:
http://www.cambridgema.gov/~/media/Files/CDD/Transportation/TrafficCalming/trcalm_brochure_2000.ashx?la=en
Generally, urban roads that have traffic where it's even possible to move at 50 mph are straight, wide and flat. That is definitely the case with Locust Ave, as seen below.
https://www.google.com/maps/@38.0343513,-78.4694989,3a,75y,173.55h,90t/data=!3m6!1e1!3m4!1sLC2p-2vz-idXmvJ1TaBg7w!2e0!7i13312!8i6656
Some suggestions for slowing traffic on this street might include:
- Put curb extensions at the sidewalks to reduce the distance that pedestrians have to walk to cross the street. This also makes the intersections tighter for cars, requiring them to slow down.
- Currently, parking is only on the left side of the street. About every half a block alternate parking between the left and the right sides causing the traffic to have to curve back and forth. This will slow down the traffic.
- Mark the parking with stripes, making the traffic lanes look smaller.
- If there is room, add another bicycle lane to the left side of the street.
Here is an example of traffic calming.
https://www.google.com/maps/@42.3652093,-71.0988748,3a,75y,14.17h,59.59t/data=!3m6!1e1!3m4!1ssPfDs88GgNpRJgOTW2Z7mA!2e0!7i13312!8i6656
Although this street is in a more dense urban area (Cambridge, MA) than Locust, it used to look similar to it. All parking was on one side, and there were no curb extensions. Now you can see the tightened intersections and the curvy traffic lanes. Speeds have dropped significantly on this road. It's worth a try.
I see a video tracking privacy issue in 3..2..1...
When pedestrians are hit at 20 mph less than 10 % die, if they are hit at 32 mph about 80% die. So anything over 20mph is fast in a residential area. This is a fact that has been used all over the world to lower the fatalities on roads, and it actually works.
The speed limit is simply incorrect. Given a relatively flat and straight road the speed is actually chosen by the comfort level of the average driver by a 80% margin. So honestly the speed limit should be increased unless there is some other factor to lower it.
I am one of those people who think speed limit changes are an issue. A city or town or highway should have consistent, predictable speed limits, so drivers "know" how fast they should be going, and can intuitively know how fast they are actually driving. ... 25mph and 35 mph, for example. EVERY residential street is 25 mph, EVERY thoroughfare is 35 mph, done. ... say 45 mph and 70 mph, or whatever ... the community can decide on the actual limits, but you only get two choices. No more. ... an unusually tight curve, for example. But don't take that to mean you can have more than two limits on otherwise ordinary streets or highways.
If in a city, I am OK with two non-freeway speeds
Same thing on a urban freeway or rural highway
I am OK with exceptions for obvious safety issues
People will learn how fast they are driving, by looking at the speedo and correlating it with how the vehicle feels. If you speed, well, then you should be consistent when you speed (I'm 5 mph over, usually), so again you know intuitively how fast you are going.
I don't like a huge set of speed limits, where in one town or city you might find 15, 20, 25, 30 ... etc mph limits posted. Now, you have to hunt for speed limit signs everywhere, instead of watching where the hell you are going.
It does lead to greater ticket revenue, and never assume that isn't the motive when your local or state/provincial government can't get it together on speed limits. It is far from unheard of for a local administration to set out to deliberately confuse drivers with constant changes in speed limits, but it's wrong and in essence is trading dollars for safety.
Keeping your eyes on the road is way more important, and will lead to much fewer accidents, than trying to fit into some traffic engineer's idea of how fast a given section of pavement is "safe" at.
If you can't build a municipal road that is safe at 25 mph, you (or your civic administration, more precisely) are failing in more ways that matter, and they should be shit-canned at once. They simply don't get it, period.
https://www.cs.virginia.edu/pe...
My God you're right! How could we have been so stupid! Clearly the reason 40,000 people are killed each year by cars is that they're all leaping in front of them! Kill the pedestrians! Kill! Kill!!!
If the government would fix the highways that would provide a route for those who want to get there quicker. Waze is sending drivers down residential streets because the highways are SLOWER. If you want to get the higher speed traffic off of the residential streets you have to provide somewhere for it to go.