Optimal traffic calming: A mixed-integer bi-level programming model for locating sidewalks and crosswalks in a multimodal transportation network to maximize pedestrians’ safety and network usability

We study the effect that installing sidewalks and crosswalks, as traffic calming facilities, has on the safety and usability of a transportation network with automobile, public transit and walking as modes of transportation. A mathematical programming model is proposed for this problem whose objective is to minimize the safety hazard for pedestrians and the total transportation cost of the network. We utilize a customized greedy heuristic and a simulated annealing algorithm for solving the problem. The computational results indicate that installing sidewalks and crosswalks at proper locations can reduce the overall transportation cost and improve pedestrians’ safety.     

基于绿色交通系统的德国城市环保交通管理策略

以绿色交通为主导的城市环保变通管理是德国城市得以可持续发展的一个重要策略.环保变通管理包括:优先发展公共交通,区域化交通安宁,促进自行车发展,汽车停车管理等一系列措施.研究揭示出环保变通管理对于德国城市摆脱汽车变通依赖的重要作用.     

Alternative marginal-cost pricing for road networks

In the literature, several studies have algebraically characterized the set of toll vectors or patterns that, when added to a user equilibrium problem, its solution would be system optimal. Toll vectors in this set are termed “valid.” While the toll vector commonly advocated in the literature, i.e., one that equates the toll on each link to its marginal external cost, is always valid, other valid toll vectors generally exist and many leave some utilized links in the network untolled. On the surface, this may appear unreasonable and seems to violate the principle of marginal-cost pricing. This note shows that, when travel demands are elastic, all valid toll vectors satisfy this principle, in that the total tolls for each path equals the congestion externality an additional traveler on the path imposes on others.     

Pareto-improving and revenue-neutral congestion pricing schemes in two-mode traffic networks

This paper studies a Pareto-improving and revenue-neutral congestion pricing scheme on a simple two-mode (highway and transit) network: this scheme aims at simultaneously improving system performance, making every individual user better off, and having zero total revenue. Different Pareto-improving situations are explored when a two-mode transportation system serves for travel groups with different value-of-time (VOT) distributions. Since the congestion pricing scheme suggested here charges transit users negative tolls and automobile users positive tolls, it can be considered as a proper way to implement congestion pricing and transit subsidy in one step, while offsetting the inequity for the poor. For a general VOT distribution of commuters, the condition of Pareto-improving is established, and the impact of the VOT distribution on solving the inequity issue is explored. For a uniform VOT distribution, we show that a Pareto-improving and revenue-neutral pricing scheme always exists for any target modal split pattern that reduces the total system travel time.     

航权开放与出口导向型服务产业发展——基于三亚旅游业发展的实证分析

为提高服务业对外开放水平、加快出口导向型服务业的国际化发展,越来越多的地方政府将航权开放提上了议事日程。本文利用我国最早开放客运航权的试点地区,海南三亚1994年至2010年间的旅游业统计数据,采用动态计量模型分析并解释航权开放对旅游业发展的影响,得到以下结论:航权和签证等消费者移动壁垒的开放进程,应与出口导向型服务业的发展水平相适应,而不是"越快越好、一放就灵";当出口导向型服务产业尚处于粗放型发展的初级阶段时,过早实施全面开放政策有可能导致客源市场结构的低端化发展、粗放型发展模式的增强循环和产业国际分工地位下降等后果,因此航权开放的最优决策应是以产业要素升级和管理体制改革进程为依据,渐进、有序地逐步开放。     

基于AHP-TOPSIS的城市轨道交通应急演练评估研究

为提升演练质量与效果,阐述城市轨道交通应急演练现状,在构建大客流综合处置演练评估指标体系的基础上,将层次分析法AHP与TOPSIS法两者有机结合,建立城市轨道交通应急演练评估模型,以城市轨道交通大客流综合处置演练为例,从协调指挥、信息传递、关键流程控制、运营恢复4个方面综合考虑影响演练效果的评估因素。通过层次分析法得出各指标权重值,采用TOPSIS法进行计算排序,针对参演各班组的演练情况进行排序,实现对城市轨道交通大客流演练的评估。经过实例验证表明,AHP-TOPSIS模型具有良好的适应性与合理性,对各种类型的应急演练评估有很好的应用价值。     

从"畅通工程"看我国城市建设和交通管理等部门的合作协调机制

近10年来,以北京、上海、广州等为典型代表的中国城市所出现的交通问题是空前严重的.所以, 国家在2000年提出了"畅通工程"作为一个重要对策.目前,"畅通工程"已实施1年多,它给人们以什么启示?在此基础上,今后我国城市建设和交通管理等部门的合作协调又该如何进行?对此,作者进行了探讨.     

秦岭生态旅游区综合交通体系架构设计探讨

为切实推动秦岭保护和文化旅游产业的开发,亟需加快完善秦岭生态旅游区综合交通体系构建。在分析秦岭生态旅游区综合交通体系现状的基础上,按照秦岭旅游区综合交通规划设想,充分发挥秦岭旅游区综合交通的功能定位,提出秦岭综合交通系统线网架构方案,形成“南北两翼,东西组团”的秦岭综合旅游交通格局。从对外交通网络建设、区内干线交通网络建设、观光慢行交通网络建设、服务保障体系建设等方面,对秦岭生态旅游区综合交通体系架构进行设计。     

Modeling current and emerging threats in the airport domain through adversarial risk analysis

Airports are critical infrastructures entailing intense human, commercial and economic activity. As such, they are preferred targets for criminal and terrorist groups, who are attracted by the promisingly high revenues they might get from an attack. Every year, airport authorities worldwide have to face, with limited resources, attacks arising from different adversaries. There are several sensible areas within an airport organization that are especially vulnerable to the terrorist threat, including, among others: (1) those related to human lives (of passengers or staff); (2) airport infrastructure (airport perimeter, main terminal, Air Traffic Control Tower, runways, hangars, etc.); (3) aircrafts and other ground vehicles; and (4) IT systems and services. Besides the more traditional ones, we are particularly concerned with attacks launched against the last type of targets, an emerging and increasingly worrisome threat. Specifically, we analyze the impact of cyber-attacks launched by organized groups whose main goal is to take hold of airport operations. In some cases, in order to have more chances to achieve their purpose (and take advantage of its eventual success), cyber attackers may be backed up by a terrorist group who will try to interfere with the Air Traffic Management network. In this paper, we aim at supporting airport authorities in their fight against both threats, by devising a security allocation plan. We provide an adversarial risk analysis model to address the problem, and apply it to obtain the optimal portfolio of preventive measures in an illustrative case study. The model is open to extensions, as e.g. larger and more complex technical infrastructures, new threats, or additional recovery measures deployed by different defensive agents.     

Bounding the inefficiency of atomic splittable selfish traffic equilibria with elastic demands

We determine the exact upper bound of the inefficiency of atomic splittable selfish traffic equilibria with elastic travel demand with and without road pricing. In the previous results, only pseudo-approximation bound were obtained for this case. By comparison, we also conclude that the traffic equilibrium with elastic demand may be worse than the corresponding fixed demand case, which implying that the demands’ elastic can have a negative effect on the quality of equilibrium solutions. Finally, we propose a road pricing mechanism. We prove that there are optimal tolls in general network, atomic players and elastic travel demand setting.