The effect of heavy vehicles on highway traffic flow (Case study: Amir Kabir freeway and Imam Ali Qom Highway)

Document Type : Original Article

Authors
Shima Aynevand 1
Alireza sarkar 2
1 M.Sc., Student, Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran.
2 Assistant Professor, Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran.
10.22034/road.2025.500470.2359
Abstract
In traffic analysis, extensive data is collected from various sources, including vehicle count, speed, location, timestamp, and more. Analyzing this data enables the identification of factors impacting traffic, including peak hours, accidents, special events, and other relevant variables, providing insights for formulating traffic improvement solutions. The present study investigates the impact of heavy vehicles on Highway traffic flow. This analytical, descriptive, and field-based study utilized data from the Qom Municipality Traffic Control Center, covering 4 hours (10:00 AM to 2:00 PM) on January 29, 2024, during which traffic congestion was observed on the Imam Ali Highway. Key metrics such as traffic volume and flow rate, flow speed, density, time headway, space headway, and vehicle speed for different times of the day were computed using traffic engineering equations. Subsequently, statistical analysis was conducted via SPSS software to examine the relationship between these metrics and the presence of heavy vehicles. The Kolmogorov-Smirnov test assessed data normality, while regression analysis evaluated the interrelations among variables. Finally, the calculated capacity from various methodological approaches was compared to the capacity recommended in the Highway Capacity Manual (HCM). The findings indicate that heavy vehicle traffic significantly contributes to congestion in adjacent lanes, underscoring the need for strategic regulations and optimal placement of toll stations on the Qom-Kashan highway to mitigate traffic challenges.
Keywords
Heavy vehicles
traffic flow
Highway
Highway Capacity Manual (HCM)
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