What about the gas guzzlers?

Posted Jun 2, 2024 15:49 UTC (Sun) by kleptog (subscriber, #1183)
In reply to: What about the gas guzzlers? by Wol
Parent article: Opt Green: KDE Eco's New Sustainable Software Project

There's a reason why traffic light intersections in the Netherlands are some of the most expensive in the world. Because they do everything: networking with other intersections to coordinate timings, changing the timings based on actual traffic flow, switching to flashing orange when traffic is low (my favourite), cameras to detect cyclists and pedestrians before they actually reach the intersection, countdown timers so you know how long you have to wait, full redundancy, support for separate tram, pedestrian & cyclist lights, all the smarts. You can have them too. They make a big difference in air quality.

Except they're apparently around €1 million per intersection, so most countries just go for simple timed lights. Worth every penny though in my opinion.

What about the gas guzzlers?

Posted Jun 2, 2024 16:06 UTC (Sun) by malmedal (subscriber, #56172) [Link] (2 responses)

Interesting, do you have a link for that?

What about the gas guzzlers?

Posted Jun 2, 2024 17:31 UTC (Sun) by rschroev (subscriber, #4164) [Link] (1 responses)

This video talks about some aspects of it: https://www.youtube.com/watch?v=knbVWXzL4-4

It doesn't go into things like the cost or the engineering involved, though.

What about the gas guzzlers?

Posted Jun 2, 2024 21:14 UTC (Sun) by kleptog (subscriber, #1183) [Link]

Somehow I guessed the maker of that video before opening it. He does great videos on traffic in the Netherlands.

He does touch on several important aspects. The traffic lights themselves are more complex and so more expensive, but that's not where the money goes. Just the planning of an intersection can cost quite a bit. It's much more than laying some asphalt, drawing some lines and calling it a day. Roads need foundations too (yay subsiding ground and rising water levels), there's dividers and colours, trams and drainage are also a consideration. Also, urban planning to remove through traffic from city centres is super important.

The reason why it works so well now is because the Netherlands started prioritising cyclists in the 70's. Since roads/intersections generally need major maintenance every 20 years or so, roads/intersections were simply upgraded when the maintainance period came round. So now many roads have already been through two upgrade cycles since then. These 3rd generation smart lights have been around for nearly 20 years which means nearly all intersections have them now.

All the cities going "oh, it's too expensive" are short sighted. Sure, it costs a bit more now and the first 10 years you won't see much benefit. But after 20 years the magic adds up and everything just starts going much smoother. It's not going to get any cheaper by waiting.

And yes, traffic light debugger is a real job :)

What about the gas guzzlers?

Posted Jun 2, 2024 19:26 UTC (Sun) by Wol (subscriber, #4433) [Link]

> Except they're apparently around €1 million per intersection, so most countries just go for simple timed lights. Worth every penny though in my opinion.

My feelings eggsackerly !!!

Even if they just switched off at night (flashing orange) when traffic is low, that would save so much in wasted fuel and unnecessary pollution.

And they don't even need to be at every junction - there's plenty of places in London where there's more than enough traffic at silly-o-clock to warrant them being on 24/7.

Cheers,
Wol

What about the gas guzzlers?

Posted Jun 4, 2024 10:33 UTC (Tue) by paulj (subscriber, #341) [Link]

Light that detect cyclists.... cry.

Here in the Celtic Isles our lights are typically modulated by pressure sensors embedded in the road, to lengthen or shorten green cycles according to whether there are cars going through a car or not and whether there are cars waiting at red on other sides. These typically sensors need at least 150 kg to trigger, according to a technician I spoke to a while ago, while waiting at lights (this was Ireland, DCC).

This is _infuriating_ if you're on a bicycle. And it means I end up ignoring red and just using common sense if there's no car behind me.

According to that technician, they can use sensors that trigger at a much lower pressure and detect cyclists, but they generally never use them.