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Self-regulating traffic lights would improve vehicle flow

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Self-regulating traffic lights would improve vehicle flow


September 16, 2010

By Ben Coxworth

Read More: http://www.gizmag.com/self-regulati...aign=473395e287-UA-2235360-4&utm_medium=email

......Not only is stopping and waiting for red lights irritating, but it is also a huge source of wasted fuel and extra CO2 emissions. Now, however, researchers have come up with something that may greatly reduce drivers’ periods in the “red light zones†– a system that allows traffic lights to monitor traffic in real time, and coordinate their signals accordingly.

Stefan Lämmer at the Dresden University of Technology and Dirk Helbing of ETH Zurich made a computer model of Dresden’s roads, in which the traffic streams flowed and merged not unlike water going through pipes. They then equipped the virtual traffic lights on those roads with sensors that monitored the local traffic flow. Using this input, each light calculated the expected number of immediately oncoming vehicles, and figured out how long it would have to stay green in order to let that traffic through.

The lights also communicated with each other and adjusted their timing based on what the lights up- and downstream were doing. There would be no sense in one light letting most of the traffic through, if it were all just going to be held up at the next one. Despite the fact that the resulting signal pattern appeared to be random and chaotic as compared to a pre-programmed pattern, the end result was a reduced waiting time of 10 to 30 percent.

Such a system would not only reduce traffic jams, but would also eliminate situations such as drivers having to wait at empty intersections, or lights cycling unnecessarily when no traffic is present.




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Its a nice idea, and if we had the money to implement it, sure, why not? As long as the same system is able to track bicycle travel and prioritize for streetcars and buses, it would certainly help the situation. I'd also be worried that having constant traffic flowing would make drivers too comfortable and not look for things like pedestrians, even though traffic flowing like water through pipes is such an appealing image.
 
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Already being done. The trouble is your flow may be interrupted by someone going very slowly in front of you, drivers making turns, pedestrians (seniors take longer to cross), weather conditions. or you maybe going in a direction different from where everyone else is going.
 
It's only being done to the extent that many intersections have sensors embedded in the road which can detect when there are or aren't cars. The best that we can do is trigger an advanced green only when necessary, or disengage a green light on a side street when there are no cars.

We certainly don't have a system in place - which would simply involve coordination of traffic lights along a corridor - to allow a car to travel any more than a few lights at a time. This is especially possible on one way streets, and there's no reason not to do it. Even in New York where lights are properly timed, cars seldomly travel faster than 40 km/hr due to the volume of traffic. There's no need to worry about the highway effect, especially with the buffer offered by parked cars.
 
Even in New York where lights are properly timed, cars seldomly travel faster than 40 km/hr due to the volume of traffic. There's no need to worry about the highway effect, especially with the buffer offered by parked cars.

Lights in New York (Manhatten) are timed for a single direction; toward lower Manhatten in the morning and out of lower Manhatten in the evening. Going across streets, from say 1st ave to 9th ave is extremely painful. Luckily, the linear island makes that uncommon.

It is impossible to time more than one direction of traffic flow for maximum efficiency. You can either go time for North on Bay and Yonge or you can go east/west on College and Dundas; our uneven intersection spacing isn't going to allow both.
 
Lights in New York (Manhatten) are timed for a single direction; toward lower Manhatten in the morning and out of lower Manhatten in the evening. Going across streets, from say 1st ave to 9th ave is extremely painful. Luckily, the linear island makes that uncommon.

It is impossible to time more than one direction of traffic flow for maximum efficiency. You can either go time for North on Bay and Yonge or you can go east/west on College and Dundas; our uneven intersection spacing isn't going to allow both.

Traffic downtown follows a T shape - the most important roads for cars are Richmond, Adelaide, University, and Jarvis. There's hardly any interference between these streets, making signal sequencing easy to implement.
 

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