These days, traffic lights are typically pre-programmed at certain times of day to have a particular rhythm, which theoretically is ideal for that area at that time. But traffic is variable, and unforeseen events like accidents or holidays can throw that off--as one of the engineers says, "that average situation never occurs." The mechanical engineers have a different idea: What if the flow of traffic controls the lights, rather than the lights controlling the flow of traffic?
Their system is adaptive, based on algorithms fed by data from both incoming and outgoing traffic at each light. The ultimate goal is what Science News calls "'the green wave', the bam, bam, bam of greens that allows platoons of vehicles to move smoothly through intersection after intersection." That wave helps both the speed of traffic and the ease of merging for any oncoming vehicle.
These lights measure the amount of traffic and beam that information to the next light, which reacts to information it's getting from all other sides and works to ensure a proper flow.
Interestingly, the team tried out their work on a section of Dresden and found some encouraging results: There was a reduction in waiting time by 56% for buses, 9% for cars and trucks, and 36% for pedestrians. The cities of Dresden and Zurich are seriously considering implementing the new system city-wide.