The effectiveness of a left-turn bypass lane on a two-lane ruralt-intersection shown by delay data was examined in this research. The bypass lane was a 12-ft-wide marked lane that through traffic mayuse 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 beconverted 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 coparison 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. This paper appearsin transportation research record no. 1299, Hov facilities and transportation systems management 1991 .
Abstract