Slashdot Mirror
Self-Adapting Traffic Lights
Roland Piquepaille writes "If you're like me, I bet you hate moments when you're in a hurry and all the traffic lights seem to intentionally switch to red just in front of your car. Now, according to Nature, a Belgian traffic researcher thinks that traffic lights that respond to local conditions could ease congestion and reduce your frustration. His method would not give you the individual power to switch the light to green. But if you were part of a group of cars approaching a red light, inexpensive traffic-flow sensors would detect your group in advance and turn the light to green. His simulations show that such adaptive traffic control is 30% more efficient than traditional ways of regulating traffic. However, his system has not been adopted by any large city. So you'll continue to be frustrated by these ?%&$! traffic lights for a while. You'll find more details and references in this overview."
My city has weight sensors laid under the tarmacs, so it knows if there are cars waiting/approaching and switches lights accordingly, or if it shall let the other direction keep going.
The real problem only arises when there are too many cards coming from all directions, and the lights will switch to the "traditional method" that is based on a predefined interval.
It's a catch-22 - Gershenson admits that the benefits wouldn't be as large in a big city where the situation is much more complex than in his simulations, however only bigger city needs to/will consider such traffic control.
Rock that crushes, Paper & Scissors that don't matter.
When I was in San Jose, CA a couple of years back, they had a system up where sensors in the road would pick up cars at intersections. They then used microwave antennae to broadcast the information to lights further down the road. So if you were driving along at night with nobody else on the road, you would get long strings of green lights going your way.
US is currently preparing for a completely different thing - a more or less massive roll-out of red-light cameras (the thing where you get you car's photograph in the mail and a red-light ticket). As a preparation for this measure, stop lights are adjusted (most of the time the duration of yellow is simply reduced) in order to increase you chances of running red light, thus increasing the profit generated by red-light tickets. (This will also increase the fatality rate, of course, but this doesn't seem to be a reason for concern.) I'm amazed how much more often these days in California I see cars crossing intersection right under my nose even when I have green. A couple of years ago I'd see something like this about once in a month. These days I see it virtually every day. In this evironment it is highly unlikely (read - impossible) that US authorities will implement anything tha will to decrease your chances of running red light. Today they prefer to make money by decresing public safety, not by increasing it. So you can forget about anything like "driver friendly" stop light for a while.