Traffic lights will often have sensors to prevent switching when no cross traffic is waiting. There are also centrally controlled systems that incorporate adapt

Traffic lights will often have sensors to prevent switching when no cross traffic is waiting. There are also centrally controlled systems that incorporate adaptive control methods. (http://en.wikipedia.org/wiki/Traffic_light_control_and_coordination#Dynamic_control http://en.wikipedia.org/wiki/Traffic_light_control_and_coord...). I think key infrastructure would probably be best left unexposed to the Internet, firewalled or not.