A Developed Approach for Modelling Overtaking Process on Egyptian Rural Roads

Overtaking is one of the complicated manoeuvres on two-lane two-way (TLTW) roads where the follower vehicles use the opposing lane to overtake the leader slower vehicles with the presence of oncoming vehicles on the opposite direction. The main objectives of the present study are (1) to modify Ghods’ overtaking gap-acceptance model for TLTW roads to be representative for Egyptian conditions, (2) to calibrate and validate both of new modified overtaking gap acceptance model and Ghods’ model, then the results have been compared, (3) to check whether new modified model to be representative to real-world collected overtakes for TLTW Egyptian roads or not. Three class II rural TLTW sites located in Dakahila Governorate are studied. Eight-hour videotaped data for sites were collected for both directions. About 82 vehicles overtook successfully but 119 failed to overtake. Modified criteria for overtaking model are derived. The 82 successful observed overtakes are used for calibration, the others 119 failed overtakes are used for validation based on the modified criteria. The modified overtaking gap-acceptance criteria are matching with successful observed overtakes on these three sites by 100% while the Ghods’ criteria are matching to them by 79.12 %. These criteria are also successfully validated on all sites. Then, the modified overtaking gap-acceptance criteria are representative for TLTW Egyptian conditions. Furthermore, the modified overtaking model was more representative to reliable collected measures (i.e. overtaking duration and overtaking distance) rather than Ghods’ and Tang’s models for TLTW Egyptian roads while they are checked using hypothesis t- test.