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Smarter programming of stoplights could improve efficiency of urban traffic

phys.org

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Re: Smarter programming of stoplights could improve efficiency of urban traffic

#31

Post by grapevines »

heydenberk wrote: post #21

It's a neat thought, and everyone who's watched a light turn red ahead of them just as they cleared a green has thought it before, but there is a serious downside. Urban stoplights should be optimized for the safety of non-motorists (pedestrians and cyclists) above all else. Giving cars more uninterrupted travel leads to higher speeds and more collisions. I'm happy that where I live there's more attention paid to tra…

>Giving cars more uninterrupted travel leads to higher speeds and more collisions

Not necessarily. In a well-timed system, cars that travel the posted speed limit are indirectly rewarded by not needing to stop. Going too fast or too slow would mean you would be out of sync with the timed system.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#32

Post by wffurr »

heydenberk wrote: post #21

It's a neat thought, and everyone who's watched a light turn red ahead of them just as they cleared a green has thought it before, but there is a serious downside. Urban stoplights should be optimized for the safety of non-motorists (pedestrians and cyclists) above all else. Giving cars more uninterrupted travel leads to higher speeds and more collisions. I'm happy that where I live there's more attention paid to tra…

You can time traffic lights to encourage calmer traffic, by having "green waves" paced for bicycles, e.g. ~15 mph. Drivers should eventually clue in and slow down between lights since it just makes them wait longer.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#33

Post by mikeyouse »

noir_lord wrote: post #24
tmoullet wrote: post #12

Earlier quoted context omitted.

I'm pretty certain there no lights that have "weight" sensors. The sensors for triggering signal changes use large induction loops to detect when ferrous metal (a car frame) is near by.

Yep as I found out with my Carbon road bike, they don't see me (or a bunch of us) which can be fun.

A strong neodymium magnet attached to your shoe or one of your components should be enough to trigger the sensor for the lights, I've seen them work on scooters and small motorcycles.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#34

Post by nerdy »

Highway commutes will be significantly streamlined when merges are done in a perfectly interlaced fashion with autonomous drivers. Anyone who has tried to get on the highway in the US during rush hour probably knows exactly what I am talking about.

Imagine driving on roads where all the vehicles followed the rules and you didn't have to pay attention and the road system worked with the vehicles to improve efficiency.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#36

Post by elithrar »

slayed0 wrote: post #7
WalterBright wrote: post #4

With all the image processing cameras out there, and the cameras already mounted on the traffic lights, it boggles the mind that nobody is making traffic light controllers that optimize traffic based on current conditions and a cost function. For example, if 5 cars are coming from one direction, turn the light red for the 1 car on the cross street. I'm pretty fed up with the light perversely stopping the 5 cars at th…

While this sounds great on paper you have to remember that traffic signals are absolutely mission critical components to the traffic system and what you are describing pushes them to the cutting edge of what many might consider "experimental" technology. There can be no trial and error. Also remember that traffic systems are not developed by start ups that can iterate quickly with seemingly endless funding and/or no…

Just to add to this:

Current traffic light controllers and/or vehicle detection system (VDS) units are also fairly ruggedised: they're designed to live in outdoor cabinets with minimal active cooling, survive up to +50C (or more) while still operating, and have long replacement lifecycles.

Modern equipment capable of processing imagery "in the field" - some kind of x86 machine - would have a hard time meeting these requirements for the same cost. Ruggedised machines do exist, but at a significant price premium.

The other option would be to ship that data back over fibre (common), but that also creates a dependency issue on the network and may require network hardware upgrades to deal with the big increase in h.264 encoded video traversing the network.

I'd love to see more of this happening, but it's an extremely conservative industry/market.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#37

Post by noir_lord »

mikeyouse wrote: post #33
noir_lord wrote: post #24

Earlier quoted context omitted.

Yep as I found out with my Carbon road bike, they don't see me (or a bunch of us) which can be fun.

A strong neodymium magnet attached to your shoe or one of your components should be enough to trigger the sensor for the lights, I've seen them work on scooters and small motorcycles.

This is an excellent idea, thanks!

Currently off my bike due to ill health but will suggest it to the cycling club.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#38

Post by Cyph0n »

shijie wrote: post #17

Or, we could use roundabouts[0] [0]: http://www.wsdot.wa.gov/Safety/roundabouts/benefits.htm

My country thinks otherwise. Roundabouts are great for low to medium traffic conditions but at high traffic they are a nightmare for any driver. The wait times can be excruciatingly long.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#39

Post by Cyph0n »

ams6110 wrote: post #29
shijie wrote: post #17

Or, we could use roundabouts[0] [0]: http://www.wsdot.wa.gov/Safety/roundabouts/benefits.htm

Roundabouts are OK but they don't work so well on multi-lane roads. The multi-lane roundabouts I've seen are confusing to most motorists and tend to slow to a crawl. The problem is there is limited space to change lanes once you are on the roundabout, so you have to enter in the proper lane based on where you want to exit. Inevitably there's someone who didn't use the proper lane and everything clogs up while they st…

They work fine here for 3 lane roads. The issue is high traffic from more than one direction simultaneously.

Re: Smarter programming of stoplights could improve efficiency of urban traffic

#40

Post by erehweb »

WalterBright wrote: post #4

With all the image processing cameras out there, and the cameras already mounted on the traffic lights, it boggles the mind that nobody is making traffic light controllers that optimize traffic based on current conditions and a cost function. For example, if 5 cars are coming from one direction, turn the light red for the 1 car on the cross street. I'm pretty fed up with the light perversely stopping the 5 cars at th…

Had a friend who worked in Energy Efficiency for a U.S. state. It was a real struggle for them to get people to switch traffic lights over to LEDs from incandescents, even though the LEDs were superior - lot of risk-aversion.
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