traffic management

Traffic management could be considered as the original smart mobility application. Electric traffic signals were first installed in 1914 in Cleveland Ohio, although London can claim an earlier implementation in 1868. The traffic signals in London were installed outside the Houses of Parliament, gas powered and used the semaphore arm adapted from a railway signal. Within a year, the installation exploded and killed the policeman operating the system. There were no more traffic signals in London for 50 years after that. The lesson – do not try an unproven technology that you are not sure will work, in a high profile location.

Since those early beginnings, traffic management has evolved into one of the most well documented, robust applications of advanced technology in transportation. While initially focused on the management of traffic conflicts intersections, advanced traffic management has expanded to include the management of freeways, express lanes, and major arterials within cities. For intersection control, the basic three, light system is still in use although the control systems for vehicle detection and timing have improved dramatically over the years. These days the best traffic signal systems are managed on a networkwide basis and feature adaptability and coordination adaptability means that the traffic signal timings are constantly reviewed and aligned to current traffic flows. 

Coordination means that the operation of one intersection takes account of the operation of surrounding intersections. The most advanced intersection control systems also have special capabilities for pedestrians and bicyclists. Special sensors can be used to detect the presence of pedestrians and give them the appropriate time, bicycles can be offered the same facility and, in many cases, special-purpose bicycle lanes allowing them to get ahead of the traffic. For freeway management a combination of sensors, telecommunications, and back-office command-and-control issues to manage routine and nonroutine conditions. This latter condition is often referred to as incident management and involves the detection, verification, clearance, and management of unusual events on the network.

Current applications also make extensive use of variable message signs to communicate to drivers with messages regarding prevailing operating conditions, emergency alerts and advisories. Express Lane management involves the same techniques with the addition of variable tolling supported by electronic toll collection, to manage the demand for transportation to specific operational objectives. For example, in most express lanes in the US, the tolls are varied to achieve an average operating speed of 45 mph on the express lanes. Typically, these facilities have non-tolled general purpose lanes that can be used as an alternative to the paid lanes.