Application for automated determination of passing and no-passing zones: A case study
Currently, passing and no-passing zones are established using a graphical technique and (or) field measurements. As an alternative, this article presents an application of two computer programs, MARKS and MARKC, developed by the authors to establish the marking of passing and no-passing zones on two-dimensional (2-D) separate and three- dimensional (3-D) combined highway alignments, respectively. Using a 7 km segment on Highway 61, a four-phase study is conducted to show the applicability of the programs, to compare the 2-D and 3-D sight distances, to determine the marking of passing and no-passing zones according to current standards, and to determine the marking according to a revised passing sight distance (PSD) model developed by the authors. The programs are shown to be accurate and applicable to real highways, and use the data that are already available in the highway agencies. A significant difference between the 2-D and 3-D sight distances is shown to exist, and therefore sight distance should be determined in 3-D combined alignments rather than 2-D separate alignments. A considerable difference is also shown between the markings according to current standards and according to the revised PSD model. It is concluded that the implementation of the developed software has the potential benefits of eliminating human errors, saving time and cost, providing greater flexibility to designers to change the alignment and easily check the effect on passing zones, and transferring the decision of allowing or disallowing passing on special circumstances from field crews to engineers. Also, revisions of the current marking standards are recommended.
|Keywords||Application, Combined alignment, Horizontal alignment, Passing zones, Sight distance, Vertical alignment|
|Journal||Canadian Journal of Civil Engineering|
Hassan, Y, Halim, A.O, & Easa, S.M. (Said M.). (1997). Application for automated determination of passing and no-passing zones: A case study. Canadian Journal of Civil Engineering, 24(2), 276–287.