this post was submitted on 18 Apr 2026
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Fuck Cars

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Overtaking and going fast in urban areas is not only dangerous, but also useless: a mathematical demonstration (www.theguardian.com)
submitted 4 weeks ago* (last edited 4 weeks ago) by lgsp@feddit.it to c/fuckcars@lemmy.world
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Those who use the bike know this very well: in the city, speeding motorists overtaking other cars, only get one thing: they arrive first to the next red.

With a simple model, the author estimated the probability that one car that overtakes another, will then be reached again at a later red light. Then he estimated the probability that the same thing will happen when there are multiple successive traffic lights, as usual in the cities.

The result is that as fast as an aggressive driver goes, the presence of multiple traffic lights makes it virtually certain that a slower driver will catch up

So, if someone aggressively overcomes you, when you reach him at the next traffic light, you can tell him that it is mathematically proven that he/she is an idiot.

In addition, this study has implications for the 30 km/h city, demonstrating how in urban areas the traffic lights determine the travel times, not the maximum speed reachable between one traffic light and the next.

The original scientific article is here: https://royalsocietypublishing.org/rsos/article/13/4/260310/481212/The-Voorhees-law-of-traffic-a-stochastic-model

crossposted from: https://poliversity.it/users/rivoluzioneurbanamobilita/statuses/116419204210303856

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[–] MachineFab812@discuss.tchncs.de 3 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

Assuming that the traffic light changes colour based on a set time cycle rather than a sensor, and that the cars are travelling on a single-lane road, the results reveal that, taking into account the probabilities of each of the four scenarios, on average the possible gains and losses in spacing between the cars balance exactly.

... that's the opposite of most lights where I live. Even at midnight hours where many switch to timed-mode, there are many that won't change at-all unless a heavy-enough vehicle is in certain lanes, and even many cars get stuck having to exercise the rules about such that were meant for motorcycles and bicycles.

[–] psud@aussie.zone 0 points 3 weeks ago (1 children)

heavy enough

It's nearly never about weight, the sensor is a metal detector my steel bike triggers lights easily, my carbon fibre bike doesn't trigger any except the newest which can see the metal in my pedals and chain in the bike area — it's really nice when you roll up to a light and see the loops embedded in the bike holding area

The bike holding area is also good, it puts bikes where drivers can't fail to see them

[–] MachineFab812@discuss.tchncs.de 0 points 3 weeks ago (1 children)

Again, making assumptions about what every light will be like. Different places installed different things at different times. Sensors fail. Programming gets updated and introduces errors. My city has a dozen or-so painted cross-walks at intersections that work as I've described previously, and without any buttons for pedestrians to push to make the light change; Those lights will NEVER change for a pedestrian at night. The "exceptions" laws stay on the books for many different reasons, reasons that will likely never go-away.

Literally no-one here is arguing against "bike holding areas"(?), but if you want to argue there should never be exceptions, exceptions made to accomodate bikes and pedestrians of all things, you're gonna have a bad time.

[–] psud@aussie.zone 0 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

Again, making assumptions about what every light will be like. Different places installed different things at different times.

Again?

It's a fair assumption, for the last 70 years electric capacitance sensors (metal detectors) have been a tiny fraction of the cost and complexity of weight sensors. I have never seen a weight sensor at traffic lights in any of the three countries I have driven in. Roads don't last 70 years, weight sensors on roads are lucky to last 20 years

https://en.wikipedia.org/wiki/Traffic_light doesn't see fit to mention any sensors other than inductive loop (metal detectors) and the long list of related things on that page don't include alternative sensors, though video sensors do also exist

No way does Germany use anything other than inductive loop detectors, unless they have Netherlands style AI camera systems to change lights before the vehicle arrives

And a search on what technologies Germany uses resulted:

  • Induction loops
  • Cameras

Weight is not included, no surprise to me as it's so expensive to maintain

[–] MachineFab812@discuss.tchncs.de 1 points 3 weeks ago* (last edited 3 weeks ago)

I live in the midwestern US. There you go assuming things again. Although, considering how much sanity and common-sense have anything to do with the decision-making of the powers-that-be in this brave, beautiful land, you've got me wondering if we're neighbors, or you could be, idk, my mayor?

That said, the traffic light situation in my town seems insane at times, but if I visit the nearest larger cities in any cardinal direction, the streets and traffic alone make me glad to come back home, so I guess you can keep knocking it out of the park and throwing facts of negligible-relavence to me in this thread, Mr. Mayor from Aussie-land.