Will robot cars drive traffic congestion off a cliff?

The computer screen in an autonomous prototype Continental Chrysler 300C sedan is seen during an event featuring numerous self-driving cars on Capitol Hill in Washington March 15, 2016. WASHINGTON -- Self-driving cars are expected to usher in a new era of mobility, safety and convenience. The problem, say transportation researchers, is that people will use them too much. Researchers believe the number of miles driven will skyrocket. It's less certain whether that will mean a corresponding surge in traffic congestion, but it's a clear possibility.