8 ms·

Ah yeah, groene golf (green wave [1]). I grew up remembering my parents also using that. Except it never bloody worked. [1] https://en.wikipedia.org/wiki/Green

by Fnoord 7y ago

Ah yeah, groene golf (green wave [1]). I grew up remembering my parents also using that. Except it never bloody worked. [1] https://en.wikipedia.org/wiki/Green_wave https://en.wikipedia.org/wiki/Green_wave

vanderZwan 7y ago
Worked fine for my family near Drachten, but that had the advantage that they also had a sign showing your speed next to the road. I suspect one issue is that the speedometer in cars are not that accurate
- SECProto 7y ago
  I live somewhere with lots of roadside speed signs (they flash speed in red if you're speeding, green if under). In the tens of cars I've driven/ridden here, the speedometer is always within a small range (±2km) of what the road sign says
  - kevin_thibedeau 7y ago
    radar detectors always read lower than your true speed since they can't be positioned directly in your line of travel.
    - SECProto 7y ago
      In the situation I experience on my commute daily: I'm 40m back and the detector is 3m perpendicular off my line of travel (reasonable approximation, as they're on a roadside light standard, the lane width is 3.5m, and the car is centered in the lane), that is a very minor discrepency. On the order of 0.2 km/h
  - perl4ever 7y ago
    There are some weird speed signs near me. One that particularly irritates me is set up to flash if you're over 25 mph. But the speed limit is 30! There's also a flashing sign by a school, that is left on at times that the regular sign specifically says the school speed limit is not in effect.
  - vanderZwan 7y ago
    The thing is that you have to look at this from the perspective of the expected largest difference between different cars, not one speedometer and actual speed. If two cars both say they drive at 50 km/h, and one is actually 45 km/h and the other 55 km/h, that is quite a bit relative margin of error. And we only need two cars like that in the whole group to start causing problems.
    - SECProto 7y ago
      But I don't think you have to look that hard at some technical error causing this variance. Drivers speeds vary between 40 and 60 pretty regularly on residential roads. Having a speedometer error doesn't even have to enter into the conversation. If you can't design a green wave to be tolerant of varying speeds, then it isn't useful.
babuskov 7y ago
Works fine in my town (population around 100k). 50kmph (around 31mph) and it's all green for some 20+ crossroads.
- jsgo 7y ago
  I'd be willing to give that a shot; I drive the speed limit in my town (population estimated at about 15.6k), but the lights seem more in relation to current traffic at the intersection. So you catch this red light and you're going straight, you stop and wait. Now when you approach the second light, because you and others were held back there was no one approaching the light so it will likely be red or turning red when you approach. To actually get out of this loop, you basically have to speed up a bit which seems like a behavior that shouldn't be rewarded as such.
  - mikestew 7y ago
    Sounds like sensor-based lights and not timed lights? Regardless, Redmond, WA is full of sensor-based lights. Hence I catch myself speeding up to an otherwise empty lane and a green light. 'cuz if I don't hurry up, it'll turn red. Timed lights work, I've seen it in action. Top of my head, Indianapolis 20 some years ago, Capitol Avenue going north I'd bet you could go from (what is effectively) Zero Street to 38th and not hit a red light.
- jandrese 7y ago
  There is a road near where I used to live that was the opposite. Speed about 10mph over the limit (55 in a 45) and it would be green all the way. Go the speed limit and you get stopped at every single light. It was shockingly reliable. The difference between speeding and going the speed limit was 15 minutes on a 20 minute drive. The only time it got broken up was the one intersection with a pedestrian crosswalk where people sometimes hit the button. Of course traffic was heavy enough that you'd be stuck behind someone doing the speed limit most days, but sometimes you got to ride the wave.
  - perl4ever 7y ago
    As I wrote in another post, there's a highway near me where you almost always hit every red light, but it's designed such that going say 20% over the limit won't work either. I believe some people deliberately go 20% under to reduce the waiting.
devicetray0 7y ago
Wow, from that article: > In the UK, in 2009, it was revealed that the Department for Transport had previously discouraged green waves as they reduced fuel usage, and thus less revenue was raised from fuel taxes. Ugh...
- smolder 7y ago
  It makes me really disappointed in the world every time I hear stories like this. Supposedly we chose 110v power over a higher voltage in the US so we could sell more copper in wires. And everyone can see Health Care is a two-faced profiteer-filled industry here.
- philjohn 7y ago
  Yes - but smart motorways are doing a pretty good job of handling congestion at peak times by keeping traffic moving at a slower pace, which ends up with everyone using less fuel ... so at least UK roads are becoming slightly better in that regard :)
- vonmoltke 7y ago
  Perverse behaviors like this are what make we worry about the calls to tax negative externalities without earmarking the funds for addressing those externalities. If you tax the externalities, but get to use the revenue for something else, what is your incentive to reduce the behavior causing the problems in the first place?
  - aeorgnoieang 7y ago
    Yes! This is a point I raise frequently. My go-to example is cigarette taxes being used to fund public schools. They should be used to cover costs (borne by the relevant government) of people smoking cigarettes! Otherwise, as has happened, school funding can be hurt by people smoking less, which is not a good situation to have created. The degree by which governments routinely violate the accounting principle of matching revenues to expenses is awful.
    - loeg 7y ago
mmjaa 7y ago
Here in Vienna, it works great. Its often quite amusing to me, as I ride a slow moped - about horse speed - and get passed by irate drivers all the time. However, I ride that green wave, while they are constantly stopping/starting at the lights ...
KirinDave 7y ago
Yes, well, the green wave is a good idea in principle, but it's sorta mistaking averages for reality. There is this thing called the "waiting time paradox" [0] (or more generally the "inspection paradox") that suggests a surprising thing, the average time between discrete events observed by many other randomly interspersed observation is the same as the average time between events. This should be surprising, because it suggests that many more people experience times LONGER than the average wait to balance out people who experience a shorter wait because they were randomly closer to the event. This happens because longer intervals, when they do exist, get a larger proportion of the random observations than the shorter intervals between events. More precisely and generically, when the quantity being observed affects the observer, the observations will be distorted by the quantity in question and have to be normalized. In the case of a green wave, those rare times when someone waits too long on a green because they were looking at their phone or a naked person in a nearby window and create slowdowns and stalls in the pipeline? Those moments are longer, so there is a longer window where you could experience them. This actually comes up a lot in observations of things in nature. Imagine if instead of light flips or bus arrivals we were observing clicks on a geiger counter and you'll realize how fundamental this is to experiencing the world. tl;dr: The Green Wave only works in averages and it can be correct even as your experience of it never working is also correct. :) [0]: https://jakevdp.github.io/blog/2018/09/13/waiting-time-paradox/ https://jakevdp.github.io/blog/2018/09/13/waiting-time-parad...

by Fnoord 7y ago

vanderZwan 7y ago

Worked fine for my family near Drachten, but that had the advantage that they also had a sign showing your speed next to the road. I suspect one issue is that the speedometer in cars are not that accurate

SECProto 7y ago
I live somewhere with lots of roadside speed signs (they flash speed in red if you're speeding, green if under). In the tens of cars I've driven/ridden here, the speedometer is always within a small range (±2km) of what the road sign says
- kevin_thibedeau 7y ago
  radar detectors always read lower than your true speed since they can't be positioned directly in your line of travel.
  - SECProto 7y ago
    In the situation I experience on my commute daily: I'm 40m back and the detector is 3m perpendicular off my line of travel (reasonable approximation, as they're on a roadside light standard, the lane width is 3.5m, and the car is centered in the lane), that is a very minor discrepency. On the order of 0.2 km/h
- perl4ever 7y ago
  There are some weird speed signs near me. One that particularly irritates me is set up to flash if you're over 25 mph. But the speed limit is 30! There's also a flashing sign by a school, that is left on at times that the regular sign specifically says the school speed limit is not in effect.
- vanderZwan 7y ago
  The thing is that you have to look at this from the perspective of the expected largest difference between different cars, not one speedometer and actual speed. If two cars both say they drive at 50 km/h, and one is actually 45 km/h and the other 55 km/h, that is quite a bit relative margin of error. And we only need two cars like that in the whole group to start causing problems.
  - SECProto 7y ago
    But I don't think you have to look that hard at some technical error causing this variance. Drivers speeds vary between 40 and 60 pretty regularly on residential roads. Having a speedometer error doesn't even have to enter into the conversation. If you can't design a green wave to be tolerant of varying speeds, then it isn't useful.

babuskov 7y ago

Works fine in my town (population around 100k). 50kmph (around 31mph) and it's all green for some 20+ crossroads.

jsgo 7y ago
I'd be willing to give that a shot; I drive the speed limit in my town (population estimated at about 15.6k), but the lights seem more in relation to current traffic at the intersection. So you catch this red light and you're going straight, you stop and wait. Now when you approach the second light, because you and others were held back there was no one approaching the light so it will likely be red or turning red when you approach. To actually get out of this loop, you basically have to speed up a bit which seems like a behavior that shouldn't be rewarded as such.
- mikestew 7y ago
  Sounds like sensor-based lights and not timed lights? Regardless, Redmond, WA is full of sensor-based lights. Hence I catch myself speeding up to an otherwise empty lane and a green light. 'cuz if I don't hurry up, it'll turn red. Timed lights work, I've seen it in action. Top of my head, Indianapolis 20 some years ago, Capitol Avenue going north I'd bet you could go from (what is effectively) Zero Street to 38th and not hit a red light.
jandrese 7y ago
There is a road near where I used to live that was the opposite. Speed about 10mph over the limit (55 in a 45) and it would be green all the way. Go the speed limit and you get stopped at every single light. It was shockingly reliable. The difference between speeding and going the speed limit was 15 minutes on a 20 minute drive. The only time it got broken up was the one intersection with a pedestrian crosswalk where people sometimes hit the button. Of course traffic was heavy enough that you'd be stuck behind someone doing the speed limit most days, but sometimes you got to ride the wave.
- perl4ever 7y ago
  As I wrote in another post, there's a highway near me where you almost always hit every red light, but it's designed such that going say 20% over the limit won't work either. I believe some people deliberately go 20% under to reduce the waiting.

devicetray0 7y ago

Wow, from that article: > In the UK, in 2009, it was revealed that the Department for Transport had previously discouraged green waves as they reduced fuel usage, and thus less revenue was raised from fuel taxes. Ugh...

smolder 7y ago
It makes me really disappointed in the world every time I hear stories like this. Supposedly we chose 110v power over a higher voltage in the US so we could sell more copper in wires. And everyone can see Health Care is a two-faced profiteer-filled industry here.
philjohn 7y ago
Yes - but smart motorways are doing a pretty good job of handling congestion at peak times by keeping traffic moving at a slower pace, which ends up with everyone using less fuel ... so at least UK roads are becoming slightly better in that regard :)
vonmoltke 7y ago
Perverse behaviors like this are what make we worry about the calls to tax negative externalities without earmarking the funds for addressing those externalities. If you tax the externalities, but get to use the revenue for something else, what is your incentive to reduce the behavior causing the problems in the first place?
- aeorgnoieang 7y ago
  Yes! This is a point I raise frequently. My go-to example is cigarette taxes being used to fund public schools. They should be used to cover costs (borne by the relevant government) of people smoking cigarettes! Otherwise, as has happened, school funding can be hurt by people smoking less, which is not a good situation to have created. The degree by which governments routinely violate the accounting principle of matching revenues to expenses is awful.
  - loeg 7y ago

mmjaa 7y ago

Here in Vienna, it works great. Its often quite amusing to me, as I ride a slow moped - about horse speed - and get passed by irate drivers all the time. However, I ride that green wave, while they are constantly stopping/starting at the lights ...

KirinDave 7y ago

Yes, well, the green wave is a good idea in principle, but it's sorta mistaking averages for reality. There is this thing called the "waiting time paradox" [0] (or more generally the "inspection paradox") that suggests a surprising thing, the average time between discrete events observed by many other randomly interspersed observation is the same as the average time between events. This should be surprising, because it suggests that many more people experience times LONGER than the average wait to balance out people who experience a shorter wait because they were randomly closer to the event. This happens because longer intervals, when they do exist, get a larger proportion of the random observations than the shorter intervals between events. More precisely and generically, when the quantity being observed affects the observer, the observations will be distorted by the quantity in question and have to be normalized. In the case of a green wave, those rare times when someone waits too long on a green because they were looking at their phone or a naked person in a nearby window and create slowdowns and stalls in the pipeline? Those moments are longer, so there is a longer window where you could experience them. This actually comes up a lot in observations of things in nature. Imagine if instead of light flips or bus arrivals we were observing clicks on a geiger counter and you'll realize how fundamental this is to experiencing the world. tl;dr: The Green Wave only works in averages and it can be correct even as your experience of it never working is also correct. :) [0]: https://jakevdp.github.io/blog/2018/09/13/waiting-time-paradox/ https://jakevdp.github.io/blog/2018/09/13/waiting-time-parad...