A study by the University of California, Berkeley, and Massachusetts Institute of Technology shows drivers from a few outlying neighborhoods travel long distances together in the same direction like schools of fish.
That results in traffic jam on area freeways.
The San Jose Mercury News ( http://bit.ly/TZtWZJ) says more than 350,000 motorists were tracked for three weeks using cellphone and GPS signals.
The California Department of Transportation and local transportation officials are examining the data and they plan to incorporate such measures as additional metering lights to spread out the traffic flow.
Information from: San Jose (Calif.) Mercury News, http://www.mercurynews.com