Capacity Calculation Method Of Multi-line Bus Stop

Public transport system is the basic infrastructure in city, and also the social commonweal concerning the national economy and the people's livelihood. Transit priority policies are not only the effective measures that release traffic jam, but also the demand of city's sustainable development. The traditional transit mode (in fact, bus) is occupying the main part of transport in a long time for the advantage of low energy and land cost, flexible operation and large coverage of network. As the nodes of transit network, bus stops are the basic facilities of bus service, also the bottleneck of traffic where a lot of traffic problems happen. Therefore, it has great theoretical significance and real world demand to built capacity calculation method basing on the real situation in China after an in-depth analysis on the vehicle behavior around and inside bus stops.Bus stops in urban area of big cities have several vivid characteristics, which include large number of bus lines, poor punctuality, and strong fluctuation of dwell time. The classic bus stop capacity calculation formula presented by HCM (Highway Capacity Manual, HCM) didn't fully considering the bus arriving and dwelling random, for this, some researcher used the stochastic service method to calculate bus stop capacity. However, the actual bus in-and-out rule can not be followed in stochastic service method. Moreover, for multi-berth bus stop, the existing models only introduce an effective berth number to show the effect of incomplete use of the berths in the capacity calculation formula, but the real situation is complicated and varied among different bus stops and different periods in the same stop, so the effective berth number is too simple and inflexible to describe the variation of capacity. Considering the disadvantage of existing methods, this dissertation develops a novel method for bus stop capacity calculation that based on the recognition and discrimination of random bus arriving time, random dwelling time and in-and-out-of-berth rule which are the facts in the operation of bus stop in urban area of big cities. Main works of this dissertation are summarized as below:(1) Introduction on the previous studies of the bus stop capacity calculation methods and discussion on the advantage and disadvantage of these methods, which include theoretical calculation method, stochastic service method, saturated headway method, statistical regression method, and simulation method. As a production, the unsuitability of these methods on the capacity calculation of bus stops in urban area is summarized and the quantity and quality of bus stop capacity are analyzed.(2) Analysis on the characteristics and trends of bus stops setting in urban area of big cities, from aspects of passenger flow distribution and land source using. As a conclusion of the analysis, the multi-lines design (there are more than one line that dwelling on the bus stop) is widely used and will be the trend in future. The practical problems happening in multi-lines stop are figured out from the real cases in the city of Beijing, and the overestimation on capacity is found to be the most fundamental and common problem. Moreover, this dissertation is analyzing the influencing factors of capacity from four aspects, including bus stop setting and interior design, bus properties and operation, passenger loading-and-unloading and arriving characteristics, and traffic surrounding.(3) Development of a novel method for capacity analysis and estimation, based on the bus arrival and dwell time distribution, as well as the designed service level. As known from the observed data, bus arrival in unit time follows Poisson distribution, and dwell time follows either negative exponential distribution or k-order Erlang distribution. The order k presents the random level of dwell time, and the bigger is k, the lower is the random level. While queue rate is selected as the measure index, and arrival distribution is set to be Poisson, the calculation models of bus stop capacity is developed separately for dwell time following negative exponential distribution and k-order Erlang distribution. As the conclusion of case study, the capacity is decreasing with the elevation of designed service level and dwell time random, furthermore when in the range of k≦ 15 especially k≦ 5, k has great effect on the capacity.(4) Development of a novel method on the two-berth bus stop capacity calculation. Deriving from the method proposed in anterior chapter, three sub-models, including queuing-to-out time sub-model, idle time sub-model and operating margin sub-model, have been established to constitute the capacity calculation model, basing on analysis about the microscopic behaviors of bus in the bus stop. From the results of case study, the effects of dwell time random level on the capacity calculation factors, the general relation between operating margin as well as capacity and queue rate, and the trend of operating margin and capacity for different service level, are analyzed.(5) Exploratory research on the three-berth bus stop capacity calculation. After situation and possibility analysis, this chapter models the queue-to-out time under different condition, then gets the average queue time model. As the conclusion of case study, the average queuing time is increasing with the elevation of traffic density and the average dwell time.