Computer-aided systems to coordinate traffic signals on urban roadways have been developed to achieve a smooth flow of traffic uninterrupted by the red phase of the signals. A new model, the traffic signal optimization model (TRASOM), has been developed that considers the three basic traffic variables: speed V, volume Q, and density, K. The model allows different road segments to have different Q-D-V relationships because traffic flow depends not only on the geometrics of the road but also on the environment and traffic conditions. Because the Q-K-V relationship defines roadway capacity as a function of speed, this relationship is an essential factor in the proper design of a progressive signal system. The objective of TRASOM is to search for the combination of control variables that results in the optimum set of dependent variables within the given constraints. The measures of performance in this decision making process may include percentage of throughput, progression speed, travel time, average and total delay, queue characteristics for left-turning traffic, or any combination of such variables. Compared to other computer-aided systems, TRASOM has simple data requirements, and output that is easy to interpret, and small implementation costs.

Media Info

  • Media Type: Digital/other
  • Pagination: pp 44-45
  • Monograph Title: Traffic control: signals and other devices
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00149224
  • Record Type: Publication
  • ISBN: 0309025664
  • Report/Paper Numbers: FCP 42l1024
  • Contract Numbers: C-1-12
  • Files: TRIS, TRB
  • Created Date: Mar 30 1977 12:00AM