Evaluation of Lane-Based Traffic Characteristics of Highways Under Mixed Traffic Conditions by Different Methods

Many researchers have concentrated on analyzing the traffic characteristics of the highway segments as a whole rather than considering individual lanes. Hence, in the present study, a comparison of the lane-based vehicle speeds and estimation of lane-based Dynamic Passenger Car Unit (DPCU) is carried out. Later, the estimated DPCU values for vehicles on Median Lane (ML) and Kerb Lane (KL), as well as the entire roadway (RW), are compared with the Indo-HCM:2017, and IRC-64:1990 suggested DPCU and PCU values, respectively. An enormous amount of traffic-related field data was collected using the infra-red sensor technique at the different highway mid-block sections in India. The macroscopic fundamental relationship diagrams among speed, flow, and density under different highway lanes such as ML and KL, and the RW, are established using the Greenshields Linear Model to determine the lane-based (ML and KL) and RW capacity. The study results reveal that the capacity estimated using the Indo-HCM:2017 and IRC-64:1990 suggested DPCU and PCU values, respectively, overestimated the lane-based capacity but underestimated the RW capacity compared to the capacity estimated using the DPCU values in this study. The analysis results also show a distinct difference between speed and DPCU values for the vehicles in different lanes and RW. Hence, proving that the assumption and use of RW speed, DPCU, and capacity values without considering the individual lanes as erroneous. The findings from this study emphasize the importance of taking lane-based characteristics into account rather than complete RW characteristics, thus addressing significant shortcomings in the previous studies. © 2021, The Institution of Engineers (India).