Modified HCM Method for Delay Estimation at Unsignalized T- Intersections: A Case Study from Delta Region, Egypt

Authors

Ahmed Mohsen Geweda, Graduate Student, Public Works Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt 35516Follow
Sayed A. Shwaly, Associate Professor Public Works Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt 35516
Usama Elrawy Shahdah, Associate Professor Public Works Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt 35516

Subject Area

Civil and Environmental Engineering

Article Type

Case Study

Abstract

This study proposes a modified gap acceptance method to estimate control delay at unsignalized intersections in Egypt. The Highway Capacity Manual (HCM) method for estimating control delay at unsignalized intersections assumes that all lower-ranking movements yield completely to higher-ranking movements. However, this assumption may not be valid in Egypt, where drivers in lower-ranking movements sometimes violate right-of-way. The proposed method introduces an adjustment factor to account for the amount of real priority that higher-ranking movements actually get from lower-ranking movements. The adjustment factor was developed based on data collected from three un-signalized T-intersections from Mansoura and Damietta cities in Egypt. The results showed that the proposed method produces relatively similar results to the observed intersection delay, with a relative difference between +0.64 and +7.31%. In contrast, the unadjusted HCM method produces a relatively high difference in the intersection delay (+1.83 and +84.59%) compared to the observed delay.

Keywords

Highway Capacity Manual (HCM), Control Delay, Unsignalized Intersections, Gap Acceptance, Conflicting Flow Rate, Egypt.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Recommended Citation

Geweda, Ahmed Mohsen; Shwaly, Sayed A.; and Shahdah, Usama Elrawy (2023) "Modified HCM Method for Delay Estimation at Unsignalized T- Intersections: A Case Study from Delta Region, Egypt," Mansoura Engineering Journal: Vol. 49 : Iss. 2 , Article 11.
Available at: https://doi.org/10.58491/2735-4202.3136