HEADWAY AND SWITCHING STRATEGIES FOR AUTOMATED VEHICULAR GROUND TRANSPORTATION SYSTEMS

The report considers the distribution of headways throughout the vehicle flow on a one-lane guideway, the splitting of such a flow at a diverging switch, and the merging of two such flows at a converging switch. The focus of the investigation was on several vehicles near a single switch, rather than on the entire system as an integrated entity. The minimum headway separating two isolated vehicles or trains is shown to be a function of time delays in information transmission and processing, uncertainties in the measurement of, and errors in, kinematic variables, emergency stopping distance, and a cost criterion pertaining to reliability and expected damage. Several alternative headway distributions among vehicles in single-lane flow are presented, and maximum flow rates are computed as functions of these strategies and system performance parameters. The propagation of velocity transients is discussed in terms of responses to the probable inputs to a single-line of traffic. It is shown that controlling headways to a single-valued function of velocity leads to undesirable responses, and that headways must include some space in excess of the minimum safe headway. In addition to the minimum headway strategies, there is a presentation of several possible merging strategies for a converging switch and of queue disciplines to yield either maximum or minimum queue lengths. (Author)

  • Corporate Authors:

    Massachusetts Institute of Technology

    Engineering Projects Laboratory
    Cambridge, MA  USA 
  • Authors:
    • GODFREY, M B
  • Publication Date: 1966-11-1

Media Info

  • Pagination: 170 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039069
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Contract Numbers: C-85-65t
  • Files: TRIS
  • Created Date: Nov 24 1973 12:00AM