Influence of Bus Stops on Flow Characteristics of Mixed Traffic
01 Aug 2005-Journal of Transportation Engineering-asce (American Society of Civil Engineers)-Vol. 131, Iss: 8, pp 640-643
TL;DR: The effects of variation of the basic parameters, such as bus dwell time, road width, and traffic flow level, are examined for both curbside and bus bay type of stops.
Abstract: The number and type of bus stops provided on a road significantly influence the flow characteristics of traffic on the road. The study of the influence of bus stops on traffic flow under homogeneous traffic conditions has been attempted by several researchers. However, studies on the influence of bus stops on traffic flow under heterogeneous traffic conditions, are found to be absent. This paper is concerned with the study of heterogeneous traffic flow characteristics using a simulation technique with specific reference to the influence of bus stops on the traffic flow. First, an overview of the microscopic traffic-flow simulation model used to study the flow characteristics of nonlane-based heterogeneous traffic on urban road links is given. Then, the validation of the model based on field observed data is described. Finally, the application of the model to study the impact of curbside bus stops and bus bays on the speeds of other vehicles in heterogeneous traffic streams is dealt with. The effects of variation of the basic parameters, such as bus dwell time, road width, and traffic flow level, are examined for both curbside and bus bay type of stops. The usefulness of the model in fixing the traffic flow levels for replacing curbside stops with bus bays, as example, has also been highlighted.
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TL;DR: The interplay between congestion and crowding externalities in the design of urban bus systems is identified and analysed and it is found that optimal bus frequency results from a trade-off between thelevel of congestion inside buses and the level of congestion outside buses.
Abstract: The interplay between congestion and crowding externalities in the design of urban bus systems is identified and analysed. A multimodal social welfare maximisation model with spatially disaggregated demand is developed, in which users choose between travelling by bus, car or walking in a transport corridor. Optimisation variables are bus fare, congestion toll, bus frequency, bus size, fare collection system, bus boarding policy and the number of seats inside buses. We find that optimal bus frequency results from a trade-off between the level of congestion inside buses, i.e., passengers’ crowding, and the level of congestion outside buses, i.e., the effect of frequency on slowing down both buses and cars in mixed-traffic roads. A numerical application shows that optimal frequency is quite sensitive to the assumptions on crowding costs, impact of buses on traffic congestion, and overall congestion level. If crowding matters to users, buses should have as many seats as possible, up to a minimum area that must be left free of seats. If for any other reason planners decide to have buses with fewer seats than optimal (e.g., to increase bus capacity), frequency should be increased to compensate for the discomfort imposed on public transport users. Finally, the consideration of crowding externalities (on both seating and standing) imposes a sizeable increase in the optimal bus fare, and consequently, a reduction of the optimal bus subsidy.
148 citations
TL;DR: A methodology for representing nonlane-based driving behavior and calibrating a microsimulation model for highly heterogeneous traffic at signalized intersection is proposed and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using genetic algorithm.
Abstract: A significant part of the world, especially in most of the Asian countries, has heterogeneous traffic characterized by diverse vehicles, changing composition, lack of lane discipline, etc., resulting in a very complex behavior. Microsimulation is, therefore, highly suited to model such traffic. However, these models need to be calibrated before their application. Although several studies have been reported in the literature on the methodologies for calibration, all of them have focused on homogeneous traffic conditions having good lane discipline. In highly heterogeneous traffic, several other factors such as traffic composition and static and dynamic characteristics of vehicles have to be considered in the calibration process. Moreover, side-by-side stacking of vehicles across the road width occurring in the absence of lane discipline should also be modeled. Hence, a methodology for representing nonlane-based driving behavior and calibrating a microsimulation model for highly heterogeneous traffic at signalized intersection is proposed. Calibration parameters were identified using sensitivity analysis, and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using genetic algorithm. The proposed methodology is illustrated using Verkehr in Staedten simulation, a widely used psychophysical car-following model based microsimulation software. Signalized intersections having diverse traffic and geometric characteristics from two cities of India are taken as a case study.
126 citations
TL;DR: It is found that bus stop spacing should be decreased if demand increases at a constant busRunning speed; however, if both bus running speed and the speed of the passenger boarding process increase, then the distance between bus stops should be kept long even at high demand levels, a result that is consistent with the implementation of Bus Rapid Transit systems that feature high bus running speeds and long distances between stops.
Abstract: This paper re-considers the problem of choosing the number of bus stops along urban routes, first by estimating the probability of stopping in low demand markets, and second by analysing the interplay between bus stop size, bus running speed, spacing and congestion in high demand markets. A comprehensive review of the theory and practice on the location and spacing of bus stops is presented. Using empirical data from Sydney, Australia, we show that the widely used Poisson model overestimates the probability of stopping in an on-call bus stopping regime, and consequently underestimates the optimal number of bus stops that should be designed. For fixed-stop services, we show that bus running speed, frequency and dwell time are crucial to determining the relationship between bus stop spacing and demand, with bus stop congestion in the form of queuing delays playing a key role. In particular, we find that bus stop spacing should be decreased if demand increases at a constant bus running speed; however, if both bus running speed and the speed of the passenger boarding process increase, then the distance between bus stops should be kept long even at high demand levels, a result that is consistent with the implementation of Bus Rapid Transit (BRT) systems that feature high bus running speeds and long distances between stops relative to conventional bus services.
96 citations
TL;DR: Investigation of the combined effect of the signalized intersection and its near-by bus stop using a two-lane CA model suggests that the capacity can be maximized by adjusting both the position of the bus stop and the cycle time, or adding a special stop lane.
Abstract: The aim of this work is to investigate the combined effect of the signalized intersection and its near-by bus stop, by using a two-lane CA model. Four cases that the stop locates upstream or downstream the intersection, and ones with the special stop lane or not are considered. The effect of the distance L D between the stop and the intersection on the capacity is studied, with respect to the traffic light cycle T and the bus dwell time T s . It is found that acting as a bottleneck, the bus stop near the intersection causes the drop of the capacity. The negative effect only appears below a critical point L Dc , which is related to the T and the T s in no stop lane cases. The larger T and T s have the tendency to create the higher loss of the capacity. While for stop lane cases, the critical value L Dc changes little. Comparisons among four cases suggest that the special stop lane can effectively enhance the capacity, and the downstream stops perform better than the upstream ones at small L D or small T or large T s . The results imply that the capacity can be maximized by adjusting both the position of the bus stop and the cycle time, or adding a special stop lane. These findings may be useful to offer scientific guidance for the management and the design of traffic networks.
81 citations
TL;DR: In this article, a bus-following model with consideration of an on-line bus station based on the properties of each bus's motion is developed. But the model is not suitable for the case of large numbers of passengers.
Abstract: In this paper, we developed a bus-following model with consideration of an on-line bus station based on the properties of each bus’s motion. The numerical results show that the proposed model can qualitatively describe the effects of an on-line bus station on each bus’s motion.
61 citations