'Self-Regulating' Traffic Lights Reduce Waiting Time
"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 researchers found that these "self-regulating" traffic lights could reduce the amount of time spent waiting at traffic signals by 10%-30%.