VEHICLE SPEEDS AND PATHS DURING FREE-FLOW MOTORWAY MERGING AND EXITING

Traffic behavior was studied at rural diamond interchanges between primary and secondary roads and the observed behavior compared with the assumptions made in geometric design. For freeway under secondary road, by far the greater part of the acceleration takes place on the entrance rather than on the acceleration lane. In these cases, the majority of drivers used the acceleration lane for final small speed adjustments and for positioning for making the merge. When considering the behavior of vehicles leaving the freeway, many vehicles actually accelerate after diverging and do not commence to decelerate until they have traveled up to 400 feet past the end of the nose; however, many drivers did commence deceleration on the designated lane, but the cars were still averaging 50 mph at the nose and heavy vehicles 45 mph.

  • Availability:
  • Supplemental Notes:
    • Proceedings of the Summer Annual Meeting: Road Design, PTRC/P/109.
  • Corporate Authors:

    Planning and Transport Res and Computation Co Ltd

    167 Oxford Street
    London W1R 1AH,   England 
  • Authors:
    • Ackroyd, L W
    • Madden, A J
  • Publication Date: 1974

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00084705
  • Record Type: Publication
  • Report/Paper Numbers: PTRC/P/109
  • Files: TRIS
  • Created Date: Jul 2 1975 12:00AM