The main goal was to convert the calculation procedures for capacity and level of service on two-lane rural highways (cf. HBS 2001, FGSV 2009) into a method which focusses on each direction separately. In addition to that some enhancements and simplifications should be implemented. At first domestic and international literature was analysed and an opinion survey and expert consultations have been conducted. Furthermore measurements of travel speeds have been performed on rural highways with variable influencing parameters (e.g. vertical and horizontal alignment, number of lanes) as well as local speed measurements and measurements of passenger car velocity profiles. Each step of the existing calculation procedure has been checked. The proposals for the procedure's improvement have been discussed within the tutor group as well as within the FGSV committees. This applies for the inclusion of separate procedures for three-lane rural highways with alternating sections for overtaking and for small divided highways with two lanes in each direction but without an emergency lane, for the conversion of the procedure for two-lane rural highways into a directional approach, for the implementation of new speed-flow diagrams for two-lane highways, for a new way of splitting a stretch of a road into several sub-sections with homogenous design parameters, for a new approach towards consideration of gradient classes and bendiness, for the proposal to dispense with considering no- passing zones as well as for the measure of effectiveness (MOE) and the procedure for estimation of level of service for a stretch of a highway composed of several sub-sections with different design parameters. By means of serial test calculations it could be assured that the enhancements and simplifications do not affect the results adversely. Based on the findings of the research project a draft for a new chapter of the German HBS was prepared and adjusted within the responsible FGSV committees simultaneously. (Author/publisher)
Samenvatting