多类型共享电动汽车出行用户特征分析

共享电动汽车作为共享经济下的新兴产物,成功融合了私家小轿车和公共交通工具的优点,成为一种新兴交通模式。本文采用问卷调查及统计分析方法对共享电动汽车细分市场下的用户需求及出行选择进行分析,揭示出多类型共享电动汽车的用户特征,以助于共享电动汽车产业发展和促进中国绿色低碳发展战略进程。     

A semi-analytical approach for solving the bottleneck model with general user heterogeneity

This paper proposes a novel semi-analytical approach for solving the dynamic user equilibrium (DUE) of a bottleneck model with general heterogeneous users. The proposed approach makes use of the analytical solutions from the bottleneck analysis to create an equivalent assignment problem that admits closed-form commute cost functions. The equivalent problem is a static and asymmetric traffic assignment problem, which can be formulated as a variational inequality problem (VIP). This approach provides a new tool to analyze the properties of the bottleneck model with general heterogeneity, and to design efficient solution methods. In particular, the existence and uniqueness of the DUE solution can be established using the P-property of the Jacobian matrix. Our numerical experiments show that a simple decomposition algorithm is able to quickly solve the equivalent VIP to high precision. The proposed VIP formation is also extended to address simultaneous departure time and route choice in a single O–D origin-destination network with multiple parallel routes.     

Paratransit Service in Indonesia: User Satisfaction and Future Choice

Abstract

This paper explores user satisfaction with making use of paratransit in Bandung, Indonesia. User perceptions of attributes are analyzed using factor analysis to find representing attribute types and factors of service quality. Ordinal probit analysis is employed to explore the characteristics of users regarding their perception of satisfaction with the paratransit service. Binary logistic analysis is undertaken to predict users’ choice probability in making use of paratransit in the future when there is a service improvement. The study reveals that what may be of importance in developed countries carries a different weight of importance for paratransit users. This fact can be explained by describing the characteristics of users that expressed their satisfaction, which also explains the target market for this mode. The analysis reveals the notion that financial motives seem to dominate when users select to use paratransit.     

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停车换乘可靠性是决定停车换乘设施能否成功吸引用户的重要因素之一.为了度量基于地铁的停车换乘可靠性,考虑了道路网上旅行时间不确定性、停车设施内搜索泊位时间不确定性和地铁车站等车不确定性,定义了“换乘可靠度”和“方式可靠度”.利用随机网络均衡分析方法模拟小汽车出行者以个人旅行时间最小为原则的旅行选择行为,包括方式选择、路径选择和停车设施选择.通过蒙特卡洛模拟和相继平均法求解均衡模型,并设计算例验证了不确定性对停车换乘分担率的显著影响.算例还分析了地铁发车频率、停车设施容量和总需求强度等因素对停车换乘可靠性的影响.     

基于多成本分析的出发时刻选择模型研究

交通问题的解决,应该从需求和供给两方面进行改善。交通需求管理通过改变出行者的出发时刻、出行路径以及出行方式等措施,将高峰期的交通需求从时间和空间2个方面进行分离,从而有效缓解城市交通压力。文中将经济学思想应用于城市道路,从固定使用成本、出行时间成本以及惩罚费用成本3个方面研究了私人小汽车出行的多成本性,通过分析居民出发时刻选择的决策过程,应用随机用户均衡分配和Logit基本理论,建立了适用于一般城市网络的出发时刻选择模型。运用模型进行一个算例分析,从而验证模型的有效性和实用性。     

Dynamic user equilibrium with side constraints for a traffic network: Theoretical development and numerical solution algorithm

This paper investigates a traffic volume control scheme for a dynamic traffic network model which aims to ensure that traffic volumes on specified links do not exceed preferred levels. The problem is formulated as a dynamic user equilibrium problem with side constraints (DUE-SC) in which the side constraints represent the restrictions on the traffic volumes. Travelers choose their departure times and routes to minimize their generalized travel costs, which include early/late arrival penalties. An infinite-dimensional variational inequality (VI) is formulated to model the DUE-SC. Based on this VI formulation, we establish an existence result for the DUE-SC by showing that the VI admits at least one solution. To analyze the necessary condition for the DUE-SC, we restate the VI as an equivalent optimal control problem. The Lagrange multipliers associated with the side constraints as derived from the optimality condition of the DUE-SC provide the traffic volume control scheme. The control scheme can be interpreted as additional travel delays (either tolls or access delays) imposed upon drivers for using the controlled links. This additional delay term derived from the Lagrange multiplier is compared with its counterpart in a static user equilibrium assignment model. If the side constraint is chosen as the storage capacity of a link, the additional delay can be viewed as the effort needed to prevent the link from spillback. Under this circumstance, it is found that the flow is incompressible when the link traffic volume is equal to its storage capacity. An algorithm based on Euler’s discretization scheme and nonlinear programming is proposed to solve the DUE-SC. Numerical examples are presented to illustrate the mechanism of the proposed traffic volume control scheme.     

Multi-class percentile user equilibrium with flow-dependent stochasticity

Travelers often reserve a buffer time for trips sensitive to arrival time in order to hedge against the uncertainties in a transportation system. To model the effects of such behavior, travelers are assumed to choose routes to minimize the percentile travel time, i.e. the travel time budget that ensures their preferred probability of on-time arrival; in doing so, they drive the system to a percentile user equilibrium (UE), which can be viewed as an extension of the classic Wardrop equilibrium. The stochasticity in the supply of transportation are incorporated by modeling the service flow rate of each road segment as a random variable. Such stochasticity is flow-dependent in the sense that the probability density functions of these random variables, from which the distribution of link travel time are constructed, are specified endogenously with flow-dependent parameters. The percentile route travel time, obtained by directly convolving the link travel time distributions in this paper, is not available in closed form in general and has to be numerically evaluated. To reveal their structural properties, percentile UE solutions are examined in special cases and verified with numerical results. For the general multi-class percentile UE traffic assignment problem, a variational inequality formulation is given and solved using a route-based algorithm. The algorithm makes use of the diagonal elements in the Jacobian of percentile route travel time, which is approximated through recursive convolution. Preliminary numerical experiments indicate that the algorithm is able to achieve highly precise equilibrium solutions.     

Modeling absolute and relative cost differences in stochastic user equilibrium problem

This paper aims to develop a hybrid closed-form route choice model and the corresponding stochastic user equilibrium (SUE) to alleviate the drawbacks of both Logit and Weibit models by simultaneously considering absolute cost difference and relative cost difference in travelers’ route choice decisions. The model development is based on an observation that the issues of absolute and relative cost differences are analogous to the negative exponential and power impedance functions of the trip distribution gravity model. Some theoretical properties of the hybrid model are also examined, such as the probability relationship among the three models, independence from irrelevant alternatives, and direct and indirect elasticities. To consider the congestion effect, we provide a unified modeling framework to formulate the Logit, Weibit and hybrid SUE models with the same entropy maximization objective but with different total cost constraint specifications representing the modelers’ knowledge of the system. With this, there are two ways to interpret the dual variable associated with the cost constraint: shadow price representing the marginal change in the entropy level to a marginal change in the total cost, and dispersion/shape parameter representing the travelers’ perceptions of travel costs. To further consider the route overlapping effect, a path-size factor is incorporated into the hybrid SUE model. Numerical examples are also provided to illustrate the capability of the hybrid model in handling both absolute and relative cost differences as well as the route overlapping problem in travelers’ route choice decisions.     

拥挤公交网络的出行费用可靠性

考虑随机事件对公交系统能力的影响,作者定义了公交网络中乘客的出行费用可靠性指标,以衡量不确定环境下的公交服务水平。该指标定义为在公交系统能力随机变化情况下,在给定的OD对之间,乘客能够按照预定费用顺利完成出行的概率。采用基于用户平衡准则的公交配流模型描述公交乘客的路径选择行为,给出了基于蒙特卡洛仿真的公交出行费用可靠性的计算方法。用一个算例对公交网络出行费用可靠性指标及其计算方法进行了验证。     

路面改造期间环境影响评估及用户成本分析

为了解由于公路占道作业对交通产生的影响,本文通过运用PARAMICS这一仿真软件模拟了20km长双向6车道一级公路在旧路面改造过程中三种不同交通负荷下的交通运行状况,并据此分别从环境影响及用户成本两方面定量化分析了公路占道作业给交通所带来的影响。通过定量化分析结果可以发现,在环境影响方面,机动车产生的温室效应及污染物排放随交通量的增长大致呈线性变化;在用户成本方面,公路占道作业致使路段车辆运行速度下降,从而造成一定时间内通过整段公路的所有车辆总燃油消耗减少,而总的用户成本却随交通量的增长呈非线性增加的趋势。