The effectiveness of a left-turn bypass lane on a two-lane rural T-intersection shown by delay data was examined in this research. The bypass lane was a 12-ft-wide marked lane that through traffic may use to move around a vehicle that has stopped to make a left turn onto the minor road of the T. Delay data were generated by the TRAF-NETSIM traffic simulation program sponsored by the FHWA. Delay can be converted into driver cost, which can be compared with the cost of constructing the lane, to provide a good indication of the point at which the extra lane would be warranted. Seven factors that may affect the need for the extra lane were tested: the opposing through volume, the opposing right-turn volume, the through volume, the left-turn volume, vehicle speed, and the distance to the nearest upstream and downstream signal. The presence of a bypass lane was also tested to allow comparison between situations with and without left-turn bypass lanes. Sixty-four simulations were run to test the factors and the interaction among factors. The results indicated that the presence of a bypass lane was a significant factor in delay, especially when higher levels of opposing and left-turn volumes were present. Significant delay and percent stops savings can be realized by including a left-turn bypass lane in certain situations.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 1-8
  • Monograph Title: HOV facilities and transportation systems management, 1991
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00615761
  • Record Type: Publication
  • ISBN: 0309051061
  • Files: TRIS, TRB, ATRI
  • Created Date: Sep 30 1991 12:00AM