Institute of Transportation, MOTC

　　In this study, we developed practical guidelines for passing lanes under various geometric and traffic characteristics on no-passing zones of two-lane rural highways, whereby a series of car-following percentage curves were developed using the TRARR model. Road authorities can obtain the alternative location, lengths and spacing of passing lanes by applying the car-following percentage curves. The road geometric data that need to be collected include grades and curve radii. The traffic characteristics that need to be determined are the two-way design hourly volume, directional split, percentage of heavy vehicles and expected car-following percentage (level of service). The developed guidelines for passing lanes have the features of easy use and adaptability to various geometric and traffic conditions.