CHRISTIANSBURG, VA. -- Even after 20 years studying the habits of aggressive drivers, Scott Geller admits he has trouble containing his shouts and curses when someone swerves in front of him on the highway. But the Virginia Tech psychologist thinks he knows a better way to deal with road rage, if only he could get other drivers to follow his lead.

The idea seems plausible enough: install a tiny green light at the back of every car, teach drivers to say "please" and "thank you" and "I'm sorry" with a series of quick flashes, and people will be less frustrated, less likely to run each other off the road.

"If someone cuts in front of you, you think, 'He did it on purpose,' " Geller said. "What if the person who cuts in front of you could quickly tell you 'I'm sorry?' "

Truckers already do this, communicating with their headlights. And motorists in some countries, such as South Africa, have been known to make their highways sparkle with conversations through hazard lights, Geller said. But commuters in most cities tend to keep to themselves and let the tension build, said Radford University professor Jerry Beasley, who approached Geller with the idea for the light system.

"We're trained on the road to be discourteous, to be aggressive," Beasley said. "People get in their cars and all of a sudden they've got a ton of power. And everything's in place to communicate violence -- people wanting to get somewhere before everyone else."

The two developed a less cumbersome system they now call The Flash. The thumb-sized light is attached with Velcro to the rear window.

Powered by the cigarette lighter, The Flash can be seen from the front and the back and is activated by pushing a remote control button.