ATIS下多用户混合均衡相对于随机社会最优的效率损失

在ATIS与道路收费共同作用的交通网络中,用户不仅在接受的交通信息上具有异质性,同时在时间价值上也具有异质性.文章基于这两类异质性,将用户分为安装ATIS并遵从信息、安装但不遵从、不安装的三类用户,所有用户均按照随机用户均衡的方式进行择路.文章构建了多用户随机均衡模型及其等价的变分不等式,并以用户感知总成本作为系统性能指标,分别建立了时间准则与费用准则下多用户随机社会最优模型.当收费不作为总成本的一部分时,研究了多用户均衡相对于随机社会最优的绝对效率损失问题.研究结论表明,无论采用何种度量准则,绝对效率损失上界与路段特性函数、出行者的社会经济特性、道路收费以及两准则下多用户均衡与随机社会最优时系统实际总出行成本均有关.     

ATIS和道路收费下混合SUE相对于SSO的效率损失

在ATIS和道路收费共同作用的异质性交通网络中,基于用户在信息接受程度与时间价值上的异质性,对用户进行合理分类,所有用户均按照随机方式进行择路.构建了多用户混合随机均衡等价的变分不等式模型,以及多用户随机社会最优模型.以用户感知的总出行成本作为系统性能评价的指标,当收费作为系统总成本的一部分时,分别在时间准则与费用准则下研究了多用户混合随机均衡相对于随机社会最优的绝对效率损失问题.研究结果表明,时间准则下的绝对效率损失上界与路段出行时间函数和混合随机均衡时系统的实际总出行时间有关,费用准则下的绝对效率损失上界还与出行者的社会经济特性和随机社会最优时系统的实际总出行时间有关.     

收费机制下利己-利他混合交通均衡分配的效率损失

运用解析推导方法对收费机制下利己-利他混合交通均衡分配问题的效率损失进行研究.首先,构建了收费机制下利己-利他混合交通均衡分配问题的等价变分不等式模型;然后,通过解析推导方法得到了收费不作为系统总出行时间成本一部分时的效率损失上界;最后,给出了路段出行时间成本函数为多项式函数时的上界表达式.研究结果表明,效率损失上界与路段出行时间成本函数类、利他系数以及出行需求划分系数相关,结论以现有文献有关结论为特例.     

界定Stackelberg博弈下的混合平衡交通网络效率损失

考虑一个受控制的交通网络,一类用户属于领导者,按照系统最优原则选择出行路径;另一类用户属于跟随者且具有不完全信息,按照Logit型随机用户平衡原则选择出行路径.建立了描述这种Stackelberg博弈下的混合平衡出行行为的变分不等式模型,给出了满足此种混合平衡的交通网络的效率损失上界,结果表明,效率损失上界与被研究的交通网络拓扑结构,交通需求及控制系数有关.     

随机需求下UE-CN混合交通均衡分配的效率损失

在交通网络中,用户的出行需求通常是随机的,而且不同类型用户的路径选择原则存在着差异.基于UE用户和CN用户路径选择原则的异质性,对随机需求下该类混合交通均衡分配的效率损失进行研究.构建了随机需求下UE-CN混合交通均衡分配的变分不等式模型;其次,运用非线性规划方法得到了路段出行时间成本为单项式函数时的效率损失上界表达式,进而探讨了需求还服从对数正态分布时的效率损失上界情况;最后,给出了数值算例.研究结果表明,单项式成本函数时的效率损失上界依赖于其最高次幂和CN用户的数目;当需求为对数正态分布时还和最大变异系数相关.数值算例表明解析方法是可行的.     

基于经典BPR阻抗函数的随机交通网络主从博弈的效率损失

现代大城市交通愈发拥堵和智能交通系统广泛应用背景下,拥堵收费、智能诱导和主从博弈、随机均衡分别是重要的管理手段和客观现象.考虑对交通网络中各路段实施收费策略,利用随机用户均衡(SUE)交通流模式研究了效率损失的上界,该交通流模式是由一部分受控于Stackelberg策略的用户所诱导产生的.假设路段时间函数是可分离的单调增的凸函数,并固定交通网络起讫点(OD)需求,在建立Logit-SUE的等价变分不等式(VI)的基础上推导出SUE和Stackelberg策略条件下交通网络的效率损失表达式.这对城市交通管理的系统决策具有重要参考价值.     

多用户多准则随机系统最优与最优收费

针对固定交通需求量和出行者的时间价值为离散分布的多准则随机交通均衡,分别研究了依费用度量和依时间度量的多用户多准则随机系统最优和最优收费问题.分别建立了基于费用和基于时间的随机系统最优的最优化模型,阐述了该模型解的唯一性条件及等价的变分不等式问题.运用变分不等式方法,研究了一阶最优收费的可行性,即能否依边际定价原则,通过收取与出行者类别无关的道路收费使多用户多准则随机均衡流与随机系统最优流一致.一阶最优收费不适用于依时间度量的随机系统最优情况,因而建立了一个最优化模型来得到此时的非歧视性道路收费.最后给出了具体算例.     

界定用户平衡及Logit型随机用户平衡下的混合平衡交通网络效率损失

考虑一个具有两类用户的交通网络,一类用户按照用户平衡原则选择出行路径,另一类用户按照Logit型随机用户平衡原则选择出行路径.建立了描述这种混合平衡出行行为的变分不等式模型,给出了满足此种混合平衡的交通网络效率损失上界,结果表明,效率损失上界与被研究的交通网络拓扑结构,交通需求及两类用户的划分比例系数有关.     

收费机制下一类随机需求混合交通均衡分配的非合作代价

运用算法博弈论探讨一类随机需求混合交通均衡分配在收费机制下的非合作代价.首先,构建了收费机制下随机需求UE-CN混合交通均衡分配的变分不等式模型.其次,运用解析推导法分别得到单项式出行成本函数下是否将收费作为系统总成本一部分时,该类混合交通均衡分配的非合作代价上界表达式.在此基础上,探讨了出行需求服从对数正态分布时的非合作代价上界表达式.并以数值算例验证所得结论.     

基于ATIS的多用户混合交通均衡分配模型

提出一个ATIS影响下的混合交通均衡分配模型,模型中考虑多类不同的用户.不同类型用户产生的出行阻抗互相影响,且阻抗影响不对称.考虑ATIS影响下的三个不同的交通系统目标:使装备用户自身的阻抗最小化、使网络中所有装备用户的出行阻抗最小化以及使网络中所有用户的出行阻抗最小化,建立了三种情形下的路段非对称干扰的多用户混合交通分配模型.将模型表示成等价的变分不等式的形式,并分析了解的存在性和唯一性条件,结果表明解虽然存在,但并非一定唯一.提出一个对角化算法来求解混合交通均衡分配模型·最后用一个简单算例表明了模型和算法的有效性.     

A multiclass,multicriteria logit-based traffic equilibrium assignment model under ATIS

This paper presents a multiclass, multicriteria (cost versus time) logit-based traffic equilibrium assignment model in road networks served by advanced traveler information systems (ATIS). All users are differentiated by their own value of time (VOT) that follows some probability distribution. Users of each class, having their own VOT, are further divided into two groups, equipped and unequipped with ATIS respectively. The travel disutility received by each user is defined as a linear bi-criteria combination of travel time and monetary travel cost. It is assumed that all users make their route choices in a logit-based stochastic manner, but the equipped users have lower perception variation on the travel disutility than the unequipped due to the ATIS service. The model is formulated as a fixed-point problem and solved by the method of successive averages in conjunction with logit assignment. Numerical results show that the traditional single-class and/or single-criterion models may overestimate or underestimate the benefit from ATIS services.     

Bounding the inefficiency of logit-based stochastic user equilibrium

Bounding the inefficiency of selfish routing has become an emerging research subject. A central result obtained in the literature is that the inefficiency of deterministic User Equilibrium (UE) is bounded and the bound is independent of network topology. This paper makes a contribution to the literature by bounding the inefficiency of the logit-based Stochastic User Equilibrium (SUE). In a stochastic environment there are two different definitions of system optimization: one is the traditional System Optimum (SO) which minimizes the total actual system travel time, and the other is the Stochastic System Optimum (SSO) which minimizes the total perceived travel time of all users. Thus there are two ways to define the inefficiency of SUE, i.e. to compare SUE with SO in terms of total actual system travel time, or to compare SUE with SSO in terms of total perceived travel time. We establish upper bounds on the inefficiency of SUE in both situations.     

Multiclass multicriteria mixed equilibrium on networks and uniform link tolls for system optimum

In this paper, we consider a unified framework of multiclass multicriteria mixed equilibrium, and the existence of uniform link tolls supporting such a mixed equilibrium as a system optimum. The network users are divided into different classes, and each class of traveler perceives his/her disutility associated with a route as a combination of two criteria given, respectively, by the travel time disutility and the time-irrelevant travel disutility. And users in a common class follow either user equilibrium (UE) principle or Cournot–Nash (CN) principle. A variational inequality model characterizing the multiclass multicriteria UE–CN mixed equilibrium behavior is developed. By utilizing the dual theory, we establish the existence of uniform link tolls supporting such mixed equilibrium as a system optimum.     

双模式交通网络中的ATIS信息定价研究

先进的出行者信息系统(ATIS)是一种服务商品,已有的研究多从提高市场占有率的角度对单模式交通网络中的ATIS进行信息定价。多模式交通网络中影响ATIS市场占有率的因素众多,而且ATIS的提供成本往往与信息质量和使用规模同时相关。因此,信息定价问题应从ATIS服务提供商利润最大化的角度进行研究。本文把ATIS信息的单次使用费用和ATIS的信息质量同时作为决策变量,将双模式路网中ATIS的定价问题描述为一个双层规划模型。其中,混合用户均衡模型为下层模型,收益模型为上层模型。然后,基于上海市虹口区的路网数据,对下层模型进行了数值分析,并讨论了相关经济效益问题。此外,本文提出了求解下层模型的MSAF算法,并进一步嵌套了粒子群(PSO)算法,最终得到ATIS服务提供商的最优ATIS信息定价和信息质量提供方案。     

A Multi-Class Dynamic User Equilibrium Model for Queuing Networks with Advanced Traveler Information Systems

This paper presents a formulation and solution algorithm for a composite dynamic user-equilibrium assignment problem with multi-user classes, in order to assess the impacts of Advanced Traveler Information Systems (ATIS) in general networks with queues. Suppose that users equipped with ATIS will receive complete information and hence be able to choose the best departure times and routes in a deterministic manner, while users not equipped with ATIS will have incomplete information and hence may make decisions on departure times and routes in a stochastic manner. This paper proposes a discrete-time, finite-dimensional variational inequality formulation that involves two criteria regarding the route and departure time choice behaviors, i.e., the deterministic dynamic user equilibrium and the nested logit-based stochastic dynamic user equilibrium. The formulation is then converted to an equivalent “zero-extreme value” minimization problem. A heuristic algorithm based on route/time-swapping process is proposed, which iteratively adjusts the route and departure time choices to reach closely to an extreme point of the minimization problem. A numerical example is used to demonstrate the effectiveness of the proposed approach for assessing the ATIS impacts such as changes in individual travel costs, departure times, route inflows, queuing peaks and total network travel cost. This revised version was published online in July 2006 with corrections to the Cover Date.     

Day-to-day evolution of the traffic network with Advanced Traveler Information System

Since the notion of user equilibrium (UE) was proposed by Wardrop [13], it has become a cornerstone for traffic assignment analysis. But, it is not sufficient to only ask whether equilibrium exists or not; it is equally important to ask whether and how the system can achieve equilibrium. Meanwhile, stability is an important performance in the sense that if equilibrium is unsustainable, both the equilibrium and the trajectory are sensitive to disturbances, even a small perturbation will result in the system evolution away from the equilibrium point. These incentive a growing interest in day-to-day dynamics. In this paper, we develop a dynamical system with Advanced Traveler Information System (ATIS) and study the stability of the network with ATIS. A simple network is used to simulate the model, and the results show that there exist periodic attractors in the traffic network in some cases (for example, the market penetration level of ATIS is 0.25 and traffic demand is 2 unit). It is found that the logit parameter of the dynamical model and the traffic demand can also affect the stability of the traffic network. More periodic attractors appear in the system when the traffic demand is large and the low logit parameter can delay the appearance of periodic attractors. By simulation, it can be concluded that if the range of the periodic attractors’ domain of the simple network is known, the road pricing based on the range of the attraction domain is effective to alleviate the instability of the system.     

A dynamic route guidance system based on real traffic data

Mobility is one of the vital goods of modern societies. One way to alleviate congestion and to utilise the existing infrastructure more efficiently are Advanced Traveller Information Systems (ATIS). To provide the road user with optimal travel routes, we propose a procedure in two steps. First on-line simulations supplemented by real traffic data are performed to calculate actual travel times and traffic loads. Afterwards these data are processed in a route guidance system which allows the road user an optimisation with regard to individual preferences. To solve this multiple criteria optimisation problem fuzzy set theory is applied to the dynamic routing problem.     

多用户类多准则交通分配的势博弈与拥挤定价

交通管理者在解决路网拥挤问题时,并不知道出行者的出行效用,同时管理者难以对出行者的路径选择行为做出准确的观测.运用势博弈理论分析多用户类多准则交通行为的演化过程,得到了固定需求和弹性需求情形下的可容许动态(一种刻画出行者通过转换路径增加当前效用的近似调整行为的演化动态),证明当路段时间函数和逆需求函数为严格单调、连续、可微时,所对应的交通分配是势博弈问题的惟一Nash均衡点.进一步研究了固定需求下的可变拥挤道路收费问题,得到了在当前系统状态下实现系统最优交通分配的拥挤收费水平.