Planner vs. Engineer is a well-known professional rivalry in the infrastructure world. The arguments are sometimes friendly, sometimes hostile, sometimes about important issues, sometimes ...

Research shows left turns at intersections are dangerous and slow traffic. Benjamin Rondel/The Image Bank via Getty Images Vikash Gayah: When you make a left turn, you have to cross oncoming traffic.

Engineers are exploring a future white phase on U.S. traffic lights, showing how autonomous vehicles could coordinate movement at intersections.

More than 60% of traffic collisions at intersections involve left turns. Some U.S. cities – including San Francisco, Salt Lake City and Birmingham, Alabama – are restricting left turns. Dr. Vikash ...