Evaluating the significance of highway network links under the flood damage: An accessibility approach

This paper conducts an analysis to assess the significance of highway network links in Maryland under flood damage. An accessibility index is derived to incorporate the distance-decay effect and the volume of traffic influence on the transportation network. The accessibility level of individual counties and the state as a whole is checked before and after the hypothetical disruption of individual links within the floodplain. The results indicate that critical links identified based on the distance-only and the distance-traffic volume criteria appear to be different, implying that the priority of retrofit might also vary depending on what criterion to choose. The percentage loss of accessibility due to the disruption of a link is generally greater in the latter. However, distance-only consideration results in a more prominent spatial distribution pattern of links in percentage loss induced. Some links remain significant in both cases. Especially if the disruption of a certain link does not have an alternative solution (for example, if the link is the only way in and out of a certain county) and if counties connected by the link are low accessibility counties, the two criteria may produce a similar outcome.     

打折的公共汽车票--闲话"外宾"

改革开放初期的时候,我和几个年纪稍长的朋友在一起聊天.那哥儿几个下海特早,按当时的标准看,已经可以被称作大款了.不知道是谁先抻的茬儿,说起砍价这件事儿来了.其中有个朋友年纪最大,见多识广,嘴上俏皮话也多.他为砍价这个话题作了一个精辟的总结,"如今这年月,除了公共汽车票不能砍价,剩下的全都能砍价儿."     

The analysis of regulation on private highway investment under a build-operate-transfer scheme

The build-operate-transfer (BOT) approach has become an attractive instrument for public facility provision, especially for a project that faces difficulty with public finance. This study analyzes the regulation alternatives on private highway investment under a BOT scheme and their impacts on traffic flows, travel costs, toll, capacity, and social welfare (total user-benefit in the traffic system including congestion). For comparison, five cases are analyzed: (1) No BOT with maximizing welfare, (2) No BOT with breaking even on finance, (3) BOT without regulation, (4) BOT with a minimum flow constraint (the total users will not be less than those in Case 1), and (5) BOT with a maximum travel cost constraint (the travel cost for users on a non-tolled road will not exceed the maximum tolerance). After each case is modeled and simulated on some functional forms, we find that the case of BOT with regulations performs between the cases of maximizing welfare and that of maximizing profit. From the perspective of the government, regulation has less power in a project with low elastic demand. Furthermore, even when the regulation is strict, a high cost-efficient firm with BOT could result in a higher level of social welfare than that without a BOT scheme.     

A unified approach for allocation of highway pavement costs

There is a need to allocate various components of highway pavement costs in a unified and consistent manner in highway cost allocation analysis. Previous cost allocation studies have not placed sufficient emphasis on this aspect. This paper presents a comprehensive approach to allocate highway pavement costs. In contrast to the elaborate disaggregate distress function approach by the 1982 Federal Cost Allocation Study, the approach presented is based upon the aggregate performance of a pavement. The methodology was developed and used in the 1983–1984 Indiana Highway Cost Allocation Study to allocate pavement construction, maintenance and rehabilitation costs.     

两步分级法在公路隧道动态施工围岩分级中的应用

《JTG D70-2004公路隧道设计规范》中定性与定量[BQ]值相结合的两步分级法从定性和定量两个角度出发,互相校验和检验,采用多因素指标进行评判,对影响围岩稳定性的分析较为全面,该方法在安徽六潜高速公路隧道中应用效果较好,为调整优化相应工程措施提供了重要依据。     

The innovation of the interstate highway system

Strategies used to deploy technological innovations are central determinants of the degree to which those innovations realize their potential effect on social and economic productivity. The U.S. Interstate highway system was a deployment mechanism for the design innovations of high-speed geometric design and the control of highway access. This strategy was defined by rigid uniform minimum standards of facility design, severely constrained alternatives for configuring the network of facilities, and an inflexible and, in some cases, inappropriate institutional structure for constructing facilities. This strategy compromised the realization of productivity improvements available through the deployment of these innovations. This paper explores the origins of this deployment strategy and generalizes to a discussion of deployment strategies for large engineered systems. It shows that each of the Interstate program's provisions derived from traditions of the agency charged with implementing it and from political expedients embraced to enact the program.     

Integrated approach to determine highway flooding and critical points of drainage

Among the natural hazards that threaten transportation infrastructure, flooding represents a major hazard to highways as it challenges their design, operation, efficiency and safety. In extreme cases, it may lead to massive obstruction of traffic and direct damages to the road structures themselves and indirect damages to the economic activity and development of the region. To enable the prevention of such consequences, and the proposition of adaptive measures for existing infrastructure, this paper presents an integrated framework to identify the most vulnerable points to flooding along a highway. This is done through the combination of remote sensing information (e.g. LiDAR based Digital Elevation Model, satellite imagery), a high-quality dataset, and a quasi-2D hydrodynamic model. The forcing condition is defined using a hyetograph associated to a storm with duration of 1 day and return period of 100 years. The selected highway is located in the Mexican state of Tabasco, where extreme precipitation events and floods are frequent. Results demonstrate the ability of the methodology to identify critical water levels along the road (h > 1.50 m) at those locations where flooding has been experienced, as well as points of inspection for the highway drainage. These locations were visited in the field and maintenance problems were detected that do increase its level of exposure. We show that this framework is useful for the generation of a flood management strategy to the analyzed highway, which includes an optimum location of adaptive measures to an anticipated more intense future climate.     

公路施工项目的进度控制

分析了影响公路施工项目进度的因素,介绍进度计划的制定和实施,提出工程进度的控制措施。     

省道215公路大修方案

针对道路不同的病害,结合省道215公路大修施工,采取了相应不同的维修方案,使道路恢复到原来的使用状态。     

高速公路改变运输

我国传统交通运输体系是以铁路为主,公路、水运、空运为辅.国民经济的发展和运输需求的变化使这种运输结构呈现很大的不适应性.     

公路养护小修保养预算中路面破损率的整理过程

公路养护小修保养预算(简称小保测算)是公路养护工作的重要组成部分,小保测算涉及指标较多,其中路面破损率是主要指标之一,需要进行路面病害调查、统计、整理计算才能求得,进而求得小保费用。从最原始的数据采集说起,详细论述小保测算中路面破损率的求算过程。     

现场冷再生技术在公路大修中的施工控制

介绍了旧沥青路面冷再生技术的现场施工流程和施工质量控制。     

治理高速公路逃费措施

结合日东高速公路收费管理工作的实践,总结出治理倒卡、闯关、假冒军车等逃费现象的方法和措施。     

Uncertainty in the context of highway appraisal

Transport planning is based on traffic forecasts which are subject to great uncertainties. These uncertainties have generally been ignored or, at least, not explicitly included in the planning process. This paper describes the principles behind the estimation of the uncertainty (or range of error) of the forecasts of a traffic model and discusses the means by which this information can be absorbed into the decision-making in transport planning projects. These principles have been applied to the appraisal of a British highway project and throughout the paper reference is made to this project in order to illustrate the results of the practical application of an explicit treatment of uncertainty. It is believed that this approach can and should be developed for application in most areas of transport planning, leading inevitably to an improvement in the quality of the decisions taken.     

A dynamic modeling approach to investigate impacts to protected and low-income populations in highway planning

Environmental justice (EJ) assessment has traditionally focused on identifying distributive effects to protected populations. Federal and State highway improvement programs have been established to stimulate economic development for these populations. While this issue has long been recognized as part of EJ initiatives, no quantitative comparisons of highway construction impacts on protected populations have been reported in the literature. This paper presents a dynamic modeling approach to investigate impacts to protected and low-Income populations in highway planning using an integrated Geographic Information System (GIS) and Genetic Algorithms (GAs) optimization framework. Using census and county level parcel data, the model integrates various socioeconomic factors into a GIS while generating highway alignments using GAs. Examples using county level census data from North Carolina are demonstrated to test the sensitivity of generated highway alignments with constrained distances from protected populations. The results indicate that it is important to consider local social and economic effects, in addition to regional planning objectives when measuring the effectiveness of feasibility studies associated with highway construction. Within the proposed modeling framework attention is directed on various EJ initiatives, such as environmental health and safety laws in minority and low-income areas. The model would help planners, designers, and policy-makers understand the intricate interrelationships among local communities, while facilitating more scientific and economically equitable planning for highway construction projects.     

冷再生技术在公路养护工程中的探索与应用

冷再生技术是一种新的施工工艺,其原理是将原路面及基层破碎后作为集料,再辅以水泥、沥青、石灰等稳定剂和一定数量的集料,经拌和、整平、碾压等工艺,重新处理后而形成新的路面基层,从而可使原路面功能得以恢复。     

The effect of contract renewal and competitive tendering on public transport costs,subsidies and ridership

In this paper, we aim to estimate the effect of contract renewal as well as competitive tendering on public transport costs, subsidies, and ridership. More specifically, we examine to what extent (multiple) contract renewals and introduction of competitive tendering for long-term public transport contracts affect ridership, operational costs and subsidies in concession areas governed by public transportation authorities from 2001 until 2013 in the Netherlands. Our identification strategy improves on the literature as we are able to control for all time-invariant unobserved factors, such as network and area characteristics by using panel data. We show that when renewing long-term contracts, operational costs are reduced by at least 10%, whereas subsidies fall even stronger. For contracts that are renewed at least twice, the reduction in costs is even more substantial and in the order of 16%. We find that the effect of competitive tendering is completely absent, suggesting that the threat of competitive tendering is sufficient in a market where the majority of concessions is competitive tendered. Contract renewal not only reduces costs and subsidies, but simultaneously increases public transport ridership by 7.7%. Furthermore the vehicle-hours elasticity of operational costs is 0.40, pointing to strong economies of density. The geographical scale elasticity of operational costs is around one, which indicates constant returns to scale with respect to the geographical size of the concession area. This suggest that the current size of the Dutch concession area is optimal with respect to costs.     

山东省干线公路交通流量发展状况分析

利用山东省干线公路2008至2011年交通量数据,分析了境内国、省道路交通流量发展状况。结果表明近年来山东省路网平均交通量持续增长,路网拥挤度有所上升。最后,根据分析结果,给出了山东省干线公路未来发展建议。     

The effects of highway development on housing prices

The purpose of this research is to estimate the effects of highway development projects on the price of housing. Transportation development projects, highways in particular, improve a certain area’s accessibility but also increase its levels of exposure to traffic intensity and noise pollution. These externalities are evaluated by homeowners and residents and are reflected in the price of housing. In this paper, we use several repeat sales model specifications, including difference-in-differences estimators, and control for neighborhood effects to examine housing price trends in the municipalities around two newly developed highways in the Netherlands. The results of the research demonstrate that changes in accessibility result in a significant positive effect on the price of housing in nearby municipalities, but that increased noise pollution and traffic intensity levels result in a decrease in prices. The findings also confirm that combining the total effects of all externalities, the effect of highway development on the price of housing is generally positive, and this effect is salient even before the project is completed due to public anticipation effects.     

The optimal dispatching of taxis under congestion: A rolling horizon approach

Taxis make an important contribution to transport in many parts of the world, offering demand‐responsive, door‐to‐door transport. In larger cities, taxis may be hailed on‐street or taken from taxi ranks. Elsewhere, taxis are usually ordered by phone. The objective of a taxi dispatcher is to maximize the efficiency of fleet utilization. While the spatial and temporal distribution of taxi requests has in general a high degree of predictability, real time traffic congestion information can be collected and disseminated to taxis by communication technologies. The efficiency of taxi dispatching may be significantly improved through the anticipation of future requests and traffic conditions. A rolling horizon approach to the optimisation of taxi dispatching is formulated, which takes the stochastic and dynamic nature of the problem into account. Numerical experiments are presented to illustrate the performances of the heuristics, taking the time dependency of travel times and passenger arrivals into account.