This paper describes field observations at a ramp merging situation and the subsequent computer modelling of the operation of a typical yield and hesitate entrance ramp and also a ramp merging control system. This system provides a smooth inter-action between merging and shoulder lane vehicles and prevents congestion on the acceleration lane. Headways are measured by loop detectors upstream of an entrance ramp and when an acceptable headway is detected, a ramp vehicle is released from a stationary position at a control signal so that it reaches the nose of the ramp at the same instant as the shoulder lane gap. The gap acceptance mode of control was studied and compared to the uncontrolled condition. This was accomplished by developing two simulation models describing a section of a motorway with an entrance ramp under control and without control. Criteria for comparison included the following figures of merit: (a) the numbers of vehicles merging with the motorway stream without delay; (b) the average time spent by ramp vehicles on the acceleration lane; and (c) the average speed of motorway vehicles at the end of the simulated section. On these criteria, gap acceptance control was found to be more effective than the uncontrolled condition and details are given of the performance of the two forms of merging control. /TRRL/

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  • Authors:
    • SALTER, R J
    • El-Hanna, FIH
  • Publication Date: 1976-6


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 30-39
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00147944
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS, ATRI
  • Created Date: May 11 1977 12:00AM