cross-posted from: https://feddit.it/post/28637207
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
And this is one reason more to limit speeds in cities to 30 kilometers per hour (20 mph).
30 is awful. I like 40 and 60 so much more. 30 might be still better than awful timed red lights.
30 is great. It’s slow enough that you have time to react to someone jumping in the middle of the street just a bit ahead of your car. In a small city you’ll get wherever you need to get within 15 minutes driving at 30.
In a big city you’ll need more time, but then again, why would you ever want to live in a big city? And if you really need to live in a big city, why would you ever drive a car and not use public transport?
I know more than few people who would not leave the big city for any reason, saying there are more opportunities to have fun or more services.
A simple answer is that using a car you maybe need less time to commute or go where you need. It is not that the public transport, if we consider the needed time, is always the fastest
That’s where my job is.
So that my commute is 30 minutes instead of 2 hours.
I used to work in a big city. I moved to a smaller city. I get paid the same and spend less money. I don’t need a car as I can walk everywhere. I have a better life now.
30 is great for bikes. The safer people feel, the more will use bikes - Paris or Copenhagen are great examples, or smaller German cities like Münster and Oldenburg.
The more people go by bike, the less car traffic you will have. A bike lane of 2,50 meters width can transport 7500 vehicles per hour - that’s equivalent to a mayor motorway. (A good example fir this is Copenhagens Cykleslangen which crosses the harbour to the South). As the comments here point out amply, the main obstacles for cars are other cars, so in a bike-friendly city, the cars that need to can travel with less obstructions. As well as ambulances, firefighters and so on (we have statistics from Paris that show the latter).
And an important consequential effect of freeing city streets for bikes is that scarce and comperatively expensive public transport capacity is freed for people which need to use it, because they either need to travel long distances, or are not healthy enough to use the bike.
Bikes and Cars do not work well together. You will never have car free cities, even in small towns in EU, if you can’t drive around it with a faster road. Cities should not be build around important short and fast traffic roads, but that is how they are grown historical. Situation in rural areas is also very different to bigger cities. I would also say 30 is far from great for bikes. Most normal people drive slower and some drive faster. Speed is not the answer. Cars and bikes need different lanes. Everything longer than ~25km to work will be for cars or public transport. A good transition to having better transport will take a long time and reducing speeds to 30 is not a good solution.
You apparently have not seen Copenhagen. And yes, going 100% car-free is difficult. But in cities, you can get rid of 95% of cars. Myself, I never had one in 40 years, having lived in many different places, not only cities.