In one of the cities I've lived in, main street works just fine if everyone travels at about 34mph.
Of course, all it takes is one wannabe speed demon rushing to the red to mess up the works.
Some people just don't get it that speeding through that area slows you and everyone else down.

In one of the cities I've lived in, main street works just fine if everyone travels at about 34mph.
Of course, all it takes is one wannabe speed demon rushing to the red to mess up the works.
Some people just don't get it that speeding through that area slows you and everyone else down.

Usually coordinated signals wouldn't be affected by such activities. They would probably make that speed demon wait. It all depends on where the sensors are placed too. If you have them between signals, you can measure the speed of the group of vehicles and see that only one is out in front and adjust your timing. If all you have is the sensors at the signals, then you'll detect the arrival of a car, but you wouldn't know if it was from the previous signal or if it pulled out of a nearby street or driveway and the timing between signals is probably based on the speed limit and traffic density. Actually, both scenarios are bad for the speeder.

Usually coordinated signals wouldn't be affected by such activities.

It breaks the flow of traffic because they end up at the next light "early" and have to fully stop as it is still red. Then when the wave of traffic behind them would normally just pass through the green light, they have to stop or slow down instead while the speeder accelerates from their dead stop, which would not have happened if the speeder had just gone with the traffic flow instead of racing ahead.

I am not sure how sensors would affect things, my experience is with what I perceive to be fixed timing "green wave" configurations.

Part of the problem is that even if a few dozen cars are working in perfect unison and all is going perfectly, it only takes one person to screw it all up. One person to pull out onto the street in front of the wave and take their merry little time getting up to speed. One person to decide to take their merry little time turning off the street. One person cutting someone off. One person deciding to smoke/text/eat/drink/whatever and drive at the same time. One person.

If we can figure out how to make it so one person can't bring it all crashing down, then I think things would be far better. Unfortunately, the only way I personally see that happening is when cars start driving themselves.

Not knowing much about it, but optimizing traffic flow in a city always sounded like one of those really challenging problems. It's hard to account for all the inputs. How independent are they? [likely not as much as we would wish] What are the boundaries? [larger making things exponentially more complex] As if you could pour increasingly greater resources into developing a better solution, for relatively minuscule returns. Then, to have to re-solve the problem over and over as things change [more traffic, road repair, intersections change, businesses open and close, etc.]. And possibly end up with a solution that is optimal under some circumstances and unstable under others.

We have a couple of cities (e.g. Hannover) where the traffic lights have additional indicators (automatically updated via sensor-driven data) that will tell you how fast you need to go to catch a green wave.
It works rather well in adjusting for changes in traffic flow.

And always remember:
Lights synchronized to 50km/h are also synchronized for 100km/h ;-)

@antilias

We have these here as well in Holland. That extra info makes it work well almost everytime. A big time and a big fuel saver for us.