U.S. researchers say cellphone and Global Position System data could lead to new strategies for alleviating city commuting traffic tie-ups. Researchers from the Massachusetts Institute of Technology and the University of California, Berkeley, tracked traffic in Boston and San Francisco and analyzed bottlenecks, using data from cell towers and GPS. The study suggests a solution to traffic jams should not involve asking all drivers to reduce their driving during commute hours, but rather should target specific communities whose drivers contribute most to congestion, a UC Berkeley release reported Thursday. While asking all commuters to cut back on rush-hour driving reduces traffic congestion somewhat, asking specific groups of drivers to stay off the road may work even better, the researchers said. Canceling or delaying the trips of 1 percent of all drivers across a road network can reduce delays caused by congestion by only about 3 percent, while canceling the trips of 1 percent of drivers from carefully selected neighborhoods would reduce the extra travel time for all other drivers in a metropolitan area by as much as 18 percent, they said. \"This is a preliminary study that demonstrates that not all drivers are contributing uniformly to congestion,\" researcher Alexandre Bayen of UC Berkeley said. \"Reaching out to everybody to change their time or mode of commute is thus not necessarily as efficient as reaching out to those in a particular geographic area who contribute most to bottlenecks.\"