2010 Science News of the Year: Numbers

The Tao of traffic lights
When a traffic light goes green can seem to hinge on whimsy rather than the number of vehicles waiting. Scientists propose speeding up traffic by making signals go with the flow (SN: 10/23/10, p. 8). Inspired by the movement of crowds through narrow spaces such as doorways, Swiss and German researchers tried a responsive, flexible approach, rather than a top-down, centralized system. Their strategy puts two sensors at each intersection: One measures incoming flow and one measures outgoing flow. Lights are coordinated with every neighboring light, giving signals at the next intersection just enough time to prepare for the incoming vehicles. A simulation of the approach that tackled the center of Dresden, Germany, reduced time in traffic by 56 percent for city trams and buses, 9 percent for cars and trucks and 36 percent for pedestrians crossing intersections. Similar approaches could help reduce the estimated 500,000 person-years that the U.S. driving population spends in traffic each year and the estimated $87 billion lost to delays.

Safe bet The same mathematical principles underlie massive economic crises and tiny fluctuations, and calamitous collapses are inevitable (SN: 4/10/10, p. 11).

Fractal foraging Sharks and other marine predators follow fractal paths when cruising for a meal, resulting in a pattern known as a Lévy walk (SN: 7/3/10, p. 15).

Finding fakes A new computer program can “see” the differences between real art pieces and impostors better than previous techniques (SN Online: 1/11/10).

Drugs you’ll like A computer algorithm picks out promising drug compounds much the same way Netflix recommends DVDs to its customers (SN Online: 4/20/10).

Surviving the marathon Competitors can avoid hitting “the wall” by calculating and keeping to a physiologically sustainable pace (SN: 11/20/10, p. 8).

Twisty math No matter the material, a maximally twisted triple-stranded rope (below) is 68 percent the length of its untwisted strands (SN: 5/8/10, p. 17).