We were driving into ‘Frisco (as the locals call it) last Friday, and they had the metering lights on at the Bay Bridge. I got to wondering about where this ingenious idea started. Wikipedia explains that Chicago first used a police officer to control entrance onto the Ike in 1963. Many cities (including Sydney!) now use the stoplight variety to control traffic flow. Caltrans estimates commuters save 20 minutes thanks to the metering lights at the Bay Bridge.