Operational and Environmental Assessment of Weaving Section for Urban Roads: Case Study, Aljouf Region, KSA

The urban weaving sections are more complex due to the various disturbing elements within the weaving section, such as lane-change situations. These turbulences reduced road capacity and increased vehicle exhaust emissions. The Highway Capacity Manual (HCM 2010) has a methodology for the analysis of weaving sections for the free highways; the methodology for the analysis of urban roads is not investigated in the HCM. Therefore, the main objective of this research is to present a systematic analysis of the factors that could potentially affect the capacity and exhaust emissions of urban weaving sections. These factors include the main road traffic volume, the weaving section length (WL), the volume ratio (VR), and the percentage of heavy vehicles (HV%). Two weaving sections were selected in the Aljouf Region, KSA; the Sakakah–Dumat Al-Jandal road. The collected data were used in the development of microsimulation using VISSIM models. The results indicated that increasing the volume ratio and percentage of heavy vehicles caused a decrease in capacity and an increase in exhaust emissions. It was discovered that the increase of weaving length resulted in increasing the capacity. However, increasing the weaving length was not beneficial for reducing exhaust emissions. Finally, regression models were developed for capacity estimation and emissions prediction of urban weaving sections based on weaving length and volume ratio, resulting in relatively high R2 values.