If you plan to hit the roads like the zillions of other drivers this holiday weekend, Avi Polus has a word of advice: patience.

A transportation engineer at Technion-Israel Institute of Technology in Haifa, Prof. Polus's concern isn't drivers' collective blood pressure but traffic flow. Like the growing number of other engineers and physicists who are hubcap-deep in the science of traffic, he is determined to explain infuriating mysteries such as phantom traffic jams (There's no bottleneck or accident at the front of this...