EVALUATION OF PASSING PROCESS ON TWO-LANE RURAL HIGHWAYS IN SPAIN USING A NEW METHODOLOGY BASED ON VIDEO DATA Corresponding

Drivers need enough Passing sight distance (PSD) to pass slower vehicles with safety. This can help to improve traffic operation on two-way two-lane highways. Existing models propose different values of PSD, according to different assumptions. Only in some cases these models were based on field data of passing maneuvers. This research proposes the design of a new methodology to observe passing maneuvers on existing highways with help of 6 video cameras installed on a fix point next to passing sections. The use of a larger number of cameras allows the complete registration of trajectories along the entire passing zone, with uniform image resolution. The methodology was applied to register a sample of 234 maneuvers on 4 passing zones. Trajectories of 58 of them were completely described and analyzed using specific restitution software. Results are compared with existing PSD models. AASHTO model proposed distances travelled on the left lane are similar to average observed distances if the passed vehicle is one truck, and between 50 and 100 m higher if one passenger car is passed. Higher differences, over 100 m, were found between measured data and PSD model of Hassan et al., especially at high design speeds. Observed average speed difference between passing and impeding vehicles is significantly higher than in all models. Variables with strongest influence on the time and distance travelled on the opposing lane are: type and speed of the passed vehicle and the length of the passing zone. Left lane time and distance increase with this length. LLORCA, C. and GARCÍA, A. 3