I live in a city where the traffic engineers are too stupid the understand the value of this...about 50% of the time I get a green light, only to immediately see the next light go red about 100 meters away. It's infuriating.
Green Wave
41–50 of 56 posts
Re: Green Wave
#42Remember folks: lights timed for 40 are also timed for 80. /s
Suppose the the period of lights is equal to the time expected to move from one light to the next, and each light is red/green for the same amount of time. You have a green wave if you pass the first light green and drive at the expected speed. But if you drive twice as fast, you reach the second light red instead of green. Now it would work if the period of lights was half the time expected to get from one light to the next, but why would that generally be the case?
Actually I think the opposite will usually hold: you will still have a green wave if you drive at the expected speed divided by an integer.
Re: Green Wave
#43Earlier quoted context omitted.
I think this phenomenon shows the importance of communicating to the drivers that a green wave system is in effect. You can't really fault people for driving myopically if they don't have high level information.
That might work, though few drivers in the U.S. heed speed limits even in construction and school zones, where there are typically large brightly-colored signs and flashing lights and the stakes are much higher. Also, since the bad behavior on display at the front of a green wave is pervasive in pretty much all traffic scenarios, it seems like a modicum of driver training might ultimately be the most foolproof approa…
>That might work, though few drivers in the U.S. heed speed limits even in construction and school zones,
Because there's nothing in it for them.
Most school zones don't have kids anywhere nearby outside two specific times of day.
Most construction zones don't actually have construction happen.
Many posted speed limits are either artificially low by statute (state laws to the tune of "if road has X then max speed limit = Y" are common), for revenue purposes or to account for a temporary condition that does not affect the entire area where the speed limit applies (e.g. a single tight curve or trucks enter/exiting during business hours).
In light of these it's no wonder so many drivers disregard posted limits since it allows them to get to their destination faster.
If drivers knew that a particular travel speed would result in hitting all greens then you can bet your ass the majority of them would drive that speed. There's a ton in it for them.
Re: Green Wave
#44> 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. Despite this government Webtag documents were only updated in 2011. It is still unclear if the economic appraisal software used to apply these guidelines has also been updated and if the new guidelines are being applied to new proj…
I am all for government taxes, government bodies that oversee food production and commerce, social welfare programs or lay down ground rules for various social activities.
It doesn't mean that I think the government totally altruistic, and working solely common good. There is often (or always) a relatively hidden agenda which is conflated with the by all means honorable motives, like covering the costs of public services, saving the climate, or protecting us from a foreign adversary.
Seldom does the ulterior motive reveal itself so clearly as in this case however. Instead thinking this is a one-off, we should really be inspired to produce or look for a service where all policy decisions were inspected not only on the aspects that the politicians or public servant say but all relevant aspects, to find out the other reasons (not necessary more "real", but relevant too).
Somewhere deep among those other reasons there may be an effect that is actually not for the common good.
Re: Green Wave
#45> 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. Despite this government Webtag documents were only updated in 2011. It is still unclear if the economic appraisal software used to apply these guidelines has also been updated and if the new guidelines are being applied to new proj…
I wonder what would be the better pay-off on aggregate: more tax revenue from extra fuel use or -- presuming people get to where they need to be more efficiently -- more tax revenue from the increased productivity/consumerism? I wonder which is better in terms of pollution and other potential negatives? So, which is net cheapest? (My money's on green waves.)
You are assuming increased taxes from productivity/consumerism would affect the Department of Transportation's Budget.
They overvalue fuel tax specially because a portion of it is earmarked directly to them.
This was real by the way, not just a libertarian talking point.
Re: Green Wave
#46This one sent me quite down the memory lane. Back in 2009, I realized a fake-iphone app pitch where the goal was to sync your music so that you can ride the green wave as a pedestrian. The music will slow down or accelerate so that by walking to the beat it guarantees you that you will go with the flow.
As it was just for a pitch, I realized a video (with the help of a friend checking for my safety) to showcase the usage : Two long-sequence shots of walking between two places in Paris and being sure to have only green lights, like 15 green lights total to be nailed when they are clearly not synchronized for you and there is people and traffic around.
It was an experience in the spiritual line of Claude Lelouch "C'était un rendez-vous".
Re: Green Wave
#47Earlier quoted context omitted.
Agreed, I once had to tell an out of towner "just drive the speed limit, you'll get all green lights."
I've noticed (because I once read somewhere) that driving 5-10mph _over_ the limit results in the best timing. This is in both Pennsylvania and Los Angeles.
The speed varies based on who's timing the lights.
Re: Green Wave
#48It used to be that an MPH or two under the speed limit would get one halfway across Denver without stopping for a light. That was a long time ago, though.
I don't drive much these days. In Washington the traffic levels can be such that the best timing in the world won't set up a green wave. On the other hand, I do manage now an then to make it half a mile or so as a pedestrian without stopping for a light. (On 16th St. NW from U to Scott Circle, a saunter will hit all the lights green; a fast walk might do the same, but I seldom bother to try that.)
Re: Green Wave
#49Great Highway [0] in San Francisco is my favorite example of this. If you drive precisely 35 mph, you'll hit green lights for about two miles. This works in both directions. I think it's possible because the lights are to allow pedestrians to cross the road, so there are no intersections with cars for the full two mile stretch. Still, I think it's a lot of fun.
Re: Green Wave
#50NYC has a bunch of these on most of the avenues that break down at rush hour but work pretty well at other times, especially on weekends when you can do miles at a time.
You can actually watch the downtown wave approach and pass when you're going uptown on Park Ave starting around 60th St (and you'll get to watch it many times as you constantly hit red lights since you're fighting the wave).