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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

#41

Post by count »

WalterBright wrote: post #25
3minus1 wrote: post #5

Virginia currently uses smart traffic signals: > Traffic-responsive signals vary the timing of the lights according to the amount of traffic. They use sensors to detect the number of vehicles on an approach. The time the light stays green adjusts to let as many drivers as possible through before the signal changes to respond to traffic coming from another direction. Back when I lived in NoVa, the lights near me had t…

Lots of lights have inductive loops to detect cars, but they are too close to the lights. The cars have already stopped by the time the loop detects them. How does the Virginia system detect the cars?

The VA system detects how many cars are waiting to ensure that as many as possible make it through in a cycle (up to a limit), not detecting them as they are inbound to keep the light green.

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

#42

Post by elsyx »

WalterBright wrote: post #28
slayed0 wrote: post #14

Earlier quoted context omitted.

That's not a terrible idea but once again you run into the issues of reliability and budget. At the end of the day you need to convince city officials to spend what little money they have remaining in their budget on your new system because it offers a greater value than all of their other proposed upgrades to the city AND that what you have is as reliable or better than the current system they have in place. This me…

The city already has no problem funding cameras mounted on every traffic light, and all kinds of other surveillance equipment. A generic, self-adapting light controller would work for probably 90% of intersections. I'm hard pressed to see how it would be that expensive. It would not be hard to put in a physical interlock so both lights could not be simultaneously green, regardless of what the software commands. I don…

I would assume mounting cameras on traffic lights is an easier sell to a city, since they can be marketed as a revenue generation device.

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

#43

Post by WalterBright »

count wrote: post #41
WalterBright wrote: post #25

Earlier quoted context omitted.

Lots of lights have inductive loops to detect cars, but they are too close to the lights. The cars have already stopped by the time the loop detects them. How does the Virginia system detect the cars?

The VA system detects how many cars are waiting to ensure that as many as possible make it through in a cycle (up to a limit), not detecting them as they are inbound to keep the light green.

That's a familiar system, but it requires a car to come to nearly a full stop before the sensor picks it up. This leads often to the lights alternating so out of phase it produces the maximum delay for both streets.

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

#46

Post by mikeyouse »

noir_lord wrote: post #37
mikeyouse wrote: post #33

Earlier quoted context omitted.

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.

No worries! Some people suggest using a stainless metal case around the magnet since they tend to oxidize a bit, but there are a few good guides around with ideas.
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