Optimizing Performance of at-grade Intersection with Bus Rapid Transit Corridor and Heterogeneous Traffic

ABSTRACTBus Rapid Transit (BRT) has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance. The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries. However, in developing countries like India, the right -of-way for most of the roads is restricted and traffic is heterogeneous in nature. Provision of BRT in existing right -of-way reduces the capacity available for other motorized traffic. As the buses travel with a certain frequency on dedicated bus- ways, the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle (MV) lanes suffers from congestion. The problem gets severe at intersections. However, if buses are operated in mixed traffic it is no more rapid transit. Hence, a solution is required to address this problem and optimize the performance of traffic as a whole. This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection, and bus lanes (beyond that) are made available to all the motorized vehicular traffic (heterogeneous traffic) at intersection. The performance evaluation is done in terms of average queue length, maximum queue length, average delay time per vehicle, vehicle throughput, average speed in network and emission of Carbon monoxide CO, mono-nitrogen oxides NOx and Volatile organic compounds (VOC). It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length, maximum queue length, average delay time per vehicle and emission per vehicle, while there is an increase in vehicle throughput and average speed of all the vehicles in the network. Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network. Results of investigation are relevant in international context. VISSIM, a microscopic simulation tool, is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry, vehicle characteristics, driving behaviour and traffic controls. The effect is investigated with different random seeds to obtain reasonable results for analysis

Effect of Turning Lane at Busy Signalized At-Grade Intersection under Mixed Traffic in India

Traffic congestion on urban roads has become a serious concern, particularly, at intersections. The performance of an intersection controls the performance of urban roads meeting at that intersection. The paper presents the effect of addition of turning lane in the middle of approach road at busy signalized at-grade intersection, narrowing the width of all lanes to keep total road width the same, in heterogeneous traffic. The traffic at intersection comprises both of vehicles and pedestrians. Their interactions along with signal cycle decide the efficiency of an intersection. A microscopic simulation tool VISSIM, has been used to model the heterogeneous (mixed) traffic under constraints of roadway geometry, vehicle characteristics, driving behaviour and traffic controls. The effect is investigated with different random seeds to obtain reasonable results for analysis. The performance evaluation is done in terms of vehicle throughput, average queue length, maximum queue length, average delay time per vehicle, average speed and emission of Carbon monoxide CO, mono-nitrogen oxides NOx, Volatile organic compounds (VOC) etc. It has been observed that on adding turning lane in the middle, of approach road the average queue length, maximum queue length, average delay time per vehicle and emission per vehicle get considerably reduced, while there is an increase in vehicle throughput and average speed of all the vehicles. The results reported in this paper clearly shows that addition of turning lane in existing intersection can reduce congestion considerably, enhancing performance of intersections and network

Performance Evaluation of Multimodal Transportation Systems

AbstractConnectivity of more than one mode to a line haul in an urban area constitutes the multimodal transport system of the city. In this paper New Delhi has been taken up as a case study to evaluate performance of multimodal transportation system (MMTS), where metro became main mode in routine public transport trips. Public transport in Delhi carries only about 60% of total vehicular person trips as against 80% of the expected population size of the city. The present bus services, metro rail and IRBT (Integrated Rail-cum-Bus Transit), if implemented as planned together are estimated to carry about 15 million trips per day by 2021. Since, all the public transport trips are multimodal, it is necessary to evaluate the performance of multimodal transportation systems. The study is divided into two phases. In the first phase, the study of travel time elements (access time, transfer time, waiting time, line-haul time, and egress time) is done. Next, the influence of access and egress times on the total travel time is examined. Use is made of a comprehensive commuter travel diary to collect detail travel time estimates. A representative commuter survey, with 460 respondents, is drawn on platform at each station of Red Line and Yellow Line (Kashmiri Gate – Saket) Delhi Metro. Implementing the Second phase of study, performance measures such as Travel Time Ratio, Level of Service, Interconnectivity Ratio, Passenger Waiting Index, and Running Index were evaluated. Interconnectivity ratio (proportion of access and egress time w.r.t total travel time) for various combinations such as Mixed-Metro-Mixed, Walk-Metro-Walk, Walk-Metro-Bus and Walk- Bus-Walk has been observed. Travel Time (defined as the time differential between private transport and public transport) ratio shows much variation with trip direction, time of day, mode used, and distance travelled, etc.,. Level of Service Indicator (Out- of-vehicle Travel Time/In-Vehicle Travel Time) ratio inferred that people spends more time out-of-vehicle as compared to that of in-vehicle. Access time, transfer time, waiting time and egress time are the most important and complex travel time elements that transport systems should consider improving its efficiency and modal share. The results can be used in planning catchment area of public transport. Access and egress (together with waiting and transfer times) appear as factors that affect effectiveness and performance of a multimodal transportation system to a larger extent as unacceptable distances are likely to reduce ridership patronage. At the same time, there are key deciding factors when a trip originates as to whether the commuter shall choose public transit over personal mode of travel

Comparative Appraisal of Metro Stations in Delhi Using Data Envelopment Analysis in a Multimodal Context

Urban public transit is a critical component for sustainable urban development and is crucial to multisector expansion of a developing economy. Continuous monitoring of infrastructure performance and assessment of its effectiveness are required to continually improve service quality. The urban agglomeration of Delhi, India, was studied for the efficacy of its multimodal urban public transit system. The toolkit used was Data Envelopment Analysis (DEA), a linear optimization technique that estimates relative efficiencies of its decision making units (DMUs) for a multitude of inputs and outputs. The study area includes the Red and Yellow lines of the Delhi Metro network. Commuter-based questionnaires were used to collect 1,328 valid responses about demographic, travel time, and quality perception parameters, which were analyzed, and relative rankings of the DMUs were evaluated. The efficiency was analyzed according to the Red and Yellow lines divided into seven corridor segments and individual stations. Results revealed efficiency scores and inefficiency slacks for which improvement strategies are proposed