| The system of freeways and interstate highways exhibit the state of the traffic problem in the United States, too many vehicles using the roadway at a given time. Overall the freeway system comprises 1% of the total roadway mileage but carries about 20% of the traffic. In urban areas, freeways comprise less than 3% of the roads but carry nearly 30% of the traffic volume (Highway Statistics, 1985). With utilization of this magnitude, the benefits which can be gained through the implementation of a traffic management system can easily justify the system's costs. When these systems are operated in a coordinated manner, providing critical information to the motorist or system operator, and controlling the vehicle movements, traffic flow through an area is improved. This integration of traffic management systems is defined as the sharing of hardware, manpower and data elements between two or more different systems. Integrated traffic management systems can be of many shapes and forms, and are appearing more often throughout the United States. A high priority has been given to the establishment of area-wide urban traffic control centers with traffic surveillance, communication and management systems for both the freeway and surface street networks. |
