The traffic stream behaves differently in a mixed traffic condition as compared to that of a homogeneous condition. In a mixed traffic condition, as the traffic behaviour is always fluctuating based on the interaction caused by the surrounding elements, it is essential that the factors which affect the dynamic nature of the traffic characteristics should be considered for the proper design of the system. The paper highlights the methodology for developing the dynamic Passenger Car Unit (PCU) under various vehicular interactions for mixed traffic conditions prevalent in India. Experiments were carried out using the micro simulation model, TRAFFICSIM, which was developed for signalised intersections by the authors and reported elsewhere. The dynamic PCU values were obtained based on the analysis of the outputs of TRAFFICSIM, for varying approach width, traffic composition, stream speed and traffic volume. Modified area occupancy concept was used to develop Dynamic PCU values in a mixed traffic condition. In the modified area occupancy method, the area occupancy of the vehicle types for various traffic compositions is compared with area occupancy of the passenger cars in a car only traffic condition having the same stream speed. The study showed that the PCU values are highly sensitive to the given traffic conditions such as approach width, traffic composition, stream speed as well as flow ratio.
The efficiency of a transportation network depends upon the performance characteristics of its various components. To improve the efficiency, proper planning and design of various facilities have to be implemented. For this, simulation models seem to be more powerful than analytical procedure. This paper focuses on simulating traffic movements at signalised intersections by developing a micro simulation model using a high level programming language. The developed model TRAFFICSIM, which is highly user friendly, is capable of simulating any traffic movements at various geometric as well as signal phasing characteristics. TRAFFICSIM is a true replication of the original traffic scenario as it is capable of updating the acceleration, lateral and linear spacing as well as deceleration characteristics which is highly influenced by the traffic behaviour and signal phasing. The validated model is then applied to determine the saturation flow models during 100% car only condition as well as mixed traffic conditions. The saturation flow model developed under 100% car only condition is s = 522w, where s is the saturation flow in pc/hr and w is the carriageway width in m. The saturation flow obtained under 100% car only both in homogeneous condition and in a mixed traffic condition is 1911 pc/hr and 1908 pc/hr respectively which shows close agreement with the HCM values.
Pedestrians are the most vulnerable road users and they are highly susceptible to conflicts at midblock crosswalk locations. They are prone to a higher risk of injury on the incident of vehicular impact and their decision making behaviour at unmarked crosswalks are more crucial than at marked crosswalks. The objective of the current study is to determine the Level of Safety thresholds and warrants for both marked and unmarked pedestrian crossing facilities at urban midblock sections under mixed traffic conditions. In this study, data were collected from four different locations of Trivandrum city including marked and unmarked crosswalks. Crossing behaviour of pedestrians for both types of crosswalks were compared by analyzing different characteristics such as gap acceptance, surrogate safety measure like post encroachment time (PET), waiting time, crossing time, platoon size, type of critical vehicle and critical gap. Multiple linear regression (MLR) technique was used to develop gap acceptance models. The study also proposes Pedestrian Level of Safety (PLS) criteria which describes the safety of pedestrians at crosswalks and warrants for crossings based on the PET values. The developed PLS thresholds and the pedestrian vehicle interaction values (PV2) were correlated to the PET values to develop the pedestrian crossing warrants.
Abstract:The behaviour of traffic system in a heterogeneous traffic condition is entirely different from that of a homogeneous condition. The awareness of the influence of heterogeneity in a road network is essential for the planners and designers of the transportation system. Vehicle delay is perhaps the most important parameter used by transportation professionals to measure the performance of signalised intersections. In a mixed traffic condition, the vehicle delays are influenced by many traffic stream characteristics, taking into consideration of vehicular as well as traffic characteristics. The paper highlights the need for developing the delay models under various vehicular interactions for mixed traffic conditions prevalent in India. Experiments were carried out using the micro simulation model, TRAFFICSIM, which was developed for signalised intersections by the authors and reported elsewhere. As an application of the model TRAFFICSIM, the effect of traffic composition on delay is estimated. Considering both the delay and the flow ratio, the concept of Level of Service at signalised intersection in a mixed traffic condition, is mentioned in the paper. Influence of the proportion of buses and three wheelers in the determination of LOS are also presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.