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This reminds me of a main street somewhere in France that rewards good drivers by giving them a non-stop flow of green lights if they drive at exactly the speed

This reminds me of a main street somewhere in France that rewards good drivers by giving them a non-stop flow of green lights if they drive at exactly the speed limit. Speeding down that street is pointless, because you are guaranteed to hit a red light if you do.

koenigdavidmj 11y ago
San Francisco has a few of these, but they're keyed to bicycle speeds (13 mph or so). On the other hand, there was an article here about something Portugal did about speeding. Basically, they would put a useless stoplight in the middle of nowhere. Normally it's green all the time, since it's not actually an intersection. If you approach it while speeding, however, it turns red.
- matthewowen 11y ago
  A number are keyed to car speeds (eg westbound on Fell from Octavia to Stanyan and on Oak in the other direction).
  - JoblessWonder 11y ago
    They end up causing me so much frustration when someone is going just below the speed needed and I can see the lights changing sooner... and sooner... until I miss it.
- syrrim 11y ago
  Couldn't people just run the red, especially if there's no intersection?
  - uremog 11y ago
    Sounds like a perfect job for a red light camera though.
  - ORioN63 11y ago
    We do. Especially at night. Normally those red lights are placed around schools and such. If you're a responsible driver, you're already driving at the speed limit at those sites.
- rconti 11y ago
  Great Highway in SF is timed to exactly 35mph IIRC.
- amagumori 11y ago
  Haha, which streets? I'm a bike messenger here in SF and haven't noticed any streets that are noticeably bike-paced. I have noticed car-paced series of lights like fell/oak/masonic in the haight where you have to book it at 30-40mph to make it through efficiently. Edit: now that i'm thinking about it, a lot of the streets in the TL, fidi, and soma are pretty well timed for bikes, but for a faster pace, like 20 or so, and maybe 25-30 for the big soma streets like folsom, howard, harrison, bryant.
  - phasmantistes 11y ago
    Valencia (between 14th and 26th) is timed at 13mph northbound in the morning, and southbound in the evening.
    - amagumori 11y ago
      Oh, you're totally right. I don't work in the mission that often, so i forgot about that.
- not_kurt_godel 11y ago
  That would never fly in America - we would prefer a method that generates revenue for the police.
AnimalMuppet 11y ago
I saw that in a small town in Middle America when I was a kid. They had a grid system, and they had the lights synced to 25 MPH. They didn't even post a speed limit - just a statement that the lights were synced. Once you realized that they were telling the truth, you drove 25 MPH. Why would you do anything else?
deleted 11y ago
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gohrt 11y ago
Most of the world does this, it's standard traffic engineering.
eric_h 11y ago
There are many streets in New York that are like this, experienced cab drivers know this and will take routes that take advantage of "cascading lights". In fact the fastest/cheapest route to prospect heights from lower manhattan is to take the williamsburg bridge to lee ave, to nostrand ave, where you can catch a long stretch of cascading lights.
a3_nm 11y ago
The French term for this is "onde verte" ("green wave"), and from memory it is/was mentioned somewhere in the French traffic code. Here is a reference (in French) https://fr.wikipedia.org/wiki/Carrefour_%C3%A0_feux#Coordinations https://fr.wikipedia.org/wiki/Carrefour_%C3%A0_feux#Coordina.... That said, as far as I know that this is specific to France at all.

koenigdavidmj 11y ago

San Francisco has a few of these, but they're keyed to bicycle speeds (13 mph or so). On the other hand, there was an article here about something Portugal did about speeding. Basically, they would put a useless stoplight in the middle of nowhere. Normally it's green all the time, since it's not actually an intersection. If you approach it while speeding, however, it turns red.

matthewowen 11y ago
A number are keyed to car speeds (eg westbound on Fell from Octavia to Stanyan and on Oak in the other direction).
- JoblessWonder 11y ago
  They end up causing me so much frustration when someone is going just below the speed needed and I can see the lights changing sooner... and sooner... until I miss it.
syrrim 11y ago
Couldn't people just run the red, especially if there's no intersection?
- uremog 11y ago
  Sounds like a perfect job for a red light camera though.
- ORioN63 11y ago
  We do. Especially at night. Normally those red lights are placed around schools and such. If you're a responsible driver, you're already driving at the speed limit at those sites.
rconti 11y ago
Great Highway in SF is timed to exactly 35mph IIRC.
amagumori 11y ago
Haha, which streets? I'm a bike messenger here in SF and haven't noticed any streets that are noticeably bike-paced. I have noticed car-paced series of lights like fell/oak/masonic in the haight where you have to book it at 30-40mph to make it through efficiently. Edit: now that i'm thinking about it, a lot of the streets in the TL, fidi, and soma are pretty well timed for bikes, but for a faster pace, like 20 or so, and maybe 25-30 for the big soma streets like folsom, howard, harrison, bryant.
- phasmantistes 11y ago
  Valencia (between 14th and 26th) is timed at 13mph northbound in the morning, and southbound in the evening.
  - amagumori 11y ago
    Oh, you're totally right. I don't work in the mission that often, so i forgot about that.
not_kurt_godel 11y ago
That would never fly in America - we would prefer a method that generates revenue for the police.

AnimalMuppet 11y ago

I saw that in a small town in Middle America when I was a kid. They had a grid system, and they had the lights synced to 25 MPH. They didn't even post a speed limit - just a statement that the lights were synced. Once you realized that they were telling the truth, you drove 25 MPH. Why would you do anything else?

deleted 11y ago

[deleted]

gohrt 11y ago

Most of the world does this, it's standard traffic engineering.

eric_h 11y ago

There are many streets in New York that are like this, experienced cab drivers know this and will take routes that take advantage of "cascading lights". In fact the fastest/cheapest route to prospect heights from lower manhattan is to take the williamsburg bridge to lee ave, to nostrand ave, where you can catch a long stretch of cascading lights.

a3_nm 11y ago

The French term for this is "onde verte" ("green wave"), and from memory it is/was mentioned somewhere in the French traffic code. Here is a reference (in French) https://fr.wikipedia.org/wiki/Carrefour_%C3%A0_feux#Coordinations https://fr.wikipedia.org/wiki/Carrefour_%C3%A0_feux#Coordina.... That said, as far as I know that this is specific to France at all.