randya

Green wave for cyclists
https://www.nieuwsuitamsterdam.nl/Eng...e_cyclists.htm

2 July 2007 - When the municipality announced it wants to introduce a green wave for cyclists, some responded in disbelief. However, Copenhagen has proven the concept is feasible.

Twelve traffic lights along a 2 km route in and out of the city have been adjusted to cyclists riding 20 kmph. Before noon, the green wave applies to traffic entering the city; after noon, to cyclists going in the opposite direction.

As a result of the green wave, cyclists’ average speed increased from 15 kmph to 20 kmph. The average speed of cars remained unchanged at little over 22 kmph, whereas buses became somewhat slower.

Copenhagen intends to create more green waves for cyclists.

Source: Fietsberaad. The website also contains a video of the green wave; however, it seems not to work for Firefox users. See also: Amsterdam bicycle plan

donnamb 

Nice.

gcl8a

Holy crap! We have several places in town where I've seen signs that say 'grøn bølge' -- I had no idea that it meant 'green wave' until now! I always thought it was some kind of speed limit, since they also have signs that show you your speed (which, I must admit, I ignored). I'll have to try it out.

I just found a little more about it all at (scroll down to "Commuter route for cyclists"):

https://www.cykelby.dk/eng/lysx.asp

I was aware of a section of town that has little 'pacing lights' on the side of the road to let you know how fast to go for the green lights (but I rarely ride this section of town):

https://www.cykelby.dk/eng/ledelys.asp

genec

The interesting thing is that this can also be done here in the US... and work for both cyclists and motorists. The lights can be timed for 35MPH motorists and 17MPH cyclists. (you time the lights for 34MPH and the cyclists ride at half that speed and still get the greens) The numbers are close enough for it to work... all you really need are enlightened traffic engineers that don't assume more lanes moving at 50MPH are the answer. (they aren't).

sbhikes

17 mph is still too fast to accommodate ordinary cyclists. 20 kph is slightly over 12 mph, which is much more accommodating.

randya

then 25 mph would work. that's about as fast as the motorists should be going in an urban area, anyway. signals in DT PDX are timed ~ 12-15 mph

Bekologist

the green wave provides.



I saw a presentation by a traffic engineer from Copenhagen; the effects of the green wave (signals timed for smooth bicycling) was one very impressive bike accomdation. He showed a graph of before and after speeds of bicyclists along the 'green wave' cooridor, and the implementation of the green wave eliminated the "stop n go" red light phenomenon familiar to many of us dedicated bicycle commuters.

bring on the green wave!

(I wonder what the VC camp's position on the green wave is? I'd bet money I know what the american dream coalition would think about it. does jf toe the ADC party line on the green wave?)

slagjumper

The green wave is a cool plan. I also like the pace lights in Odense. Around here there are a few places where the lights are timed somewhere around 22mph and that seems ok for some cyclists. Nothing formal just happens that they thought through the timing and since they are within site of each other, you can pace yourself. But for the majority of new cyclists 22 is still a challenge.

I wonder if the green wave and pace lights would even work in the states. I know that for me I'd use the timed lights for driving and cycling. How many motorists would feel that it was paternalistic and just speed and wait at the light?

makeinu

How would this automatically be effective for both 17mph and 35mph traffic? If that were true then lights timed for 50mph would also work for 12.5mph cycling traffic.

oilfreeandhappy

Sounds interesting, but who's riding a bicycle to get there faster? If I make a light, great! But if I don't, that's fine too. All the motorists sitting at the light in their hot cars, can envy me out in the cool open air.

joelpalmer

Out in the cool air? Would be nice but for 4-5 months a year B'more doesn't know cool air. For me it's not so much about faster as easier. If I could settle into a pace and not have to stop every 3rd block for a red light it would be great. Of course, this is a city that can't even slightly synchronize the lights for cars, so this is just a dream unless I move.

genec

While that is true... unless the roads are wide enough to easily share, those 50MPH motorists are going to be quite irritated (and no doubt readily express it) when they have to drive at 12MPH... a difference in speed of 4X.

Whereas a difference in speed of only 2X is quite a bit more reasonable and vastly more enjoyable.

Of course lights timed at 50MPH also work at 100MPH. Enjoy your ride.

Bikepacker67

Why would you assume that they wouldn't view this as a positive?
(If I'm reading your inference correctly)

I don't think that is true.
Lights timed for 100mph, will work for 50mph travellers, but not vice versa.

genec

Sure they will... you just make twice as many lights.

Bikepacker67

Are you sure?

Say we have a 10 mile strip with a light every 1 mile.
Set to allow a 50mph vehicle to have all green lights, each light will change 1 minute and 12 seconds after the previous light (the time it takes for a 50mph vehicle to cover 1 mile)

If a vehicle went thru the first green light at 100mph, it would cover that mile in half the time, and wait the other half at a red light.

1ply

^^ and the driver would be one unhappy camper having to hit the brakes from 100mph. He'd be replacing his pads every year and imagine the fuel consumption

genec

I may be wrong on that one...

makeinu

Then when the lights start turning red they will also change 1:12 apart. So even if someone traveling 25mph makes it past the first light they will still get stuck at the second light.

If the lights are timed for 50mph traffic then they only work for 50mph traffic. I don't know where people are getting this idea that there is anything special about integer multiples.

Bikepacker67

You're right that integer multiples won't work, but fractions will.

Again, let's use a 10 mile stretch with lights every 1 mile, but this time let's make it simpler for me... the lights are timed for a vehicle travelling at 60mph, and we have a bicycle travelling at 15mph. That makes for nice round numbers in the minutes it takes to cover a mile. For the car it would be 1 minute, and for our courageous cyclist, 4 minutes.

The car and the bike take off from the first green light, and a minute later the second light turns green, and the vehicle glides on thru. Of course our cyclist has only covered a 1/4 mile, so he misses the cycle, but a minute later, it will turn green.... but this time our hero has now only covered 1/2 mile....so once again he misses the light, but it doesn't matter because he's still travelling at 15mph, given that he's 1/2 mile away. A minute after that, he's 3/4's of a mile away, and misses THAT cycle, but then....

Do you see where this is going?

genec

Yeah... fractions work... whole multiples don't. I agree. My 100MPH statement was wrong.

UmneyDurak

Wish Irvine did the same. Here you can't go a block without stopping at red light. Heck some left turning lights don't even trigger for motorcycles! Very very very car centric.

Dahon.Steve

Here's what's going to happen.

With the lights remaining green for longer periods, average speeds for the motorist will increase as they too will benefit from not having to stop for red lights. I don't like the fact that speeds in city limits will increase for the motorist and prefer the system we have today.

In my town, the cars can only travel 4 city blocks before stopping for a red light. As a cyclists, I would prefer the cars to stop at every other block lowering their average speed to 15 mph! I've seen this in New York City and it's quite effective and better for cyclist than having lots of green lights with motorist traveling at high speeds!

Dahon.Steve

Agreed.

I'm more afraid of fast traffic in the city then red lights. We shouldn't wish for long green lights because that makes it more dangerous for everyone. Unless there were two sets of lights, one for the motorist and one for the cyclist.

gcl8a

You have assumed that the second green cycles every minute, which is not necessarily true, since you have not accounted for the length of red.

While it certainly is possible to have two different wave speeds, it's more complicated than this.

Bikepacker67

I disagree.
The length of the red (green for the cross-streets) is simply adjusted down so as to allow the light to be green for the main drag, once every minute.

Not that complicated, really.