The original 1920s traffic lights were mechanically interlocked with railroad crossing signals in many American cities, forcing traffic to stop whenever a train approached within a mile—a system that persisted until the 1960s because removing the interlocks would have required renegotiating complex municipal contracts between city governments and railroad companies, making train scheduling accidentally the primary factor determining urban traffic flow patterns for decades.
Car Fact #146 — November 8, 2026
