Life cycle cost of flexible pavements and climate variability: case studies from Virginia

Abstract

Climate factors have not become a typical metric to consider for pavement life cycle cost analysis (LCCA). Changes in climate may affect pavement rutting, roughness, and cracking and lead to consequent changes in maintenance decision-making and life cycle costs. This study develops a methodology to incorporate the effects of climate variability into flexible pavement LCCA and to derive the additional life cycle costs incurred due to changes in climate. Case studies were performed for three road sections in Virginia (US) to demonstrate the methodology, using approximate mean climate change trends predicted for the investigated regions. It is estimated that climate change will incur additional vehicle operating costs ranging between US$2.30 and $4.40 on average per vehicle/annum if roads are used under a 2050 high greenhouse gas emission scenario and without being maintained. Assuming responsive maintenance, the budget demand for maintenance will arrive much earlier in the pavements’ life cycles (7–11?years earlier under the 2050 high-emission scenario). This is found to add up to 64% of agency costs (net present value) to repair each kilometre of the investigated roads in a 40-year design life. Agencies need to be aware of earlier or more frequent demands on their maintenance budgets.     

江苏省道路交通事故成因新思考及其对策

在人、车、路组成的道路系统中,“人”常被作为交通事故发生的最主要原因,而道路因素视为次要。通过江苏省交通事故原因统计和美国联邦公路管理局(FHWA)提出的事故成因总结,分析了道路状况对人的判断、操作的影响,并对江苏省交通事故成因重新进行了较科学的分析。最后,针对事故原因分析,提出了对道路设计要求、道路养护改造要求和修改相关法规等相应对策和建议。     

Life cycle cost analysis based on the fundamental cost contributors for asphalt pavements

A life cycle costing system should include the key variables that drive future costs in order to provide a framework for reducing the risk of under- or overestimating the future costs for maintenance and rehabilitation activities. In Sweden, price of oil products is mostly affected by the global economy rather than by the national economy. Whereas the price index of oil products has had a high fluctuation in different time periods, the cost fluctuation related to labour and equipment has been steady and followed the consumer price index (CPI). Contribution of the oil products was shown to be more than 50% of the total costs regarding construction and rehabilitation of asphalt pavements in Sweden. Consequently, it was observed that neither Swedish road construction price index (Vägindex) nor CPI has properly reflected the price trend regarding the asphalt pavement construction at the project level. Therefore, in this study, a framework is suggested in which energy- and time-related costs are treated with different inflation indices in order to perform a better financial risk assessment regarding future costs.     

A Markov‐Based Road Maintenance Optimization Model Considering User Costs

User costs of different maintenance actions need to be assessed in road maintenance as well as the maintenance costs. The vehicle operating cost (VOC) and the travel delay cost are two major components of the user costs associated with road maintenance actions. This article simplifies the general calculation models of these two user cost components and develops a multiobjective Markov‐based model to minimize both maintenance cost and user cost subject to a number of constraints including the average annual budget limit and the performance requirement. The road deterioration process is modeled as a discrete‐time Markov process, the states of road performance are defined in terms of the road roughness, and the state transition probabilities are estimated considering the effects of deterioration and maintenance actions. An example is provided to illustrate the use of the proposed road maintenance optimization model. The results show that the optimal road maintenance plan obtained from the model is practical to implement and is cost‐effective compared with the periodical road maintenance plan. The results also indicate that the maintenance cost and the user cost are competitive. When maintenance works are carried out more frequently, the life‐cycle maintenance costs will increase while the life‐cycle user costs will decrease. This is because the VOC contributes the most amount of the user cost and its change has a contrary trend to the change of the maintenance cost over time.     

高速公路沥青路面全寿命经济分析

为了进一步提高公路建设的投资效益,在分析高速公路沥青路面耐久性和寿命周期关系的基础上,建立了沥青路面全寿命周期费用模型,该模型综合考虑了投资方案的初始修建费、未来的养护维修费、用户费用和寿命期内的其它相关费用。介绍了沥青路面全寿命经济分析的方法,讨论了全寿命经济分析过程中需要重点考虑的两个问题——沥青路面使用性能衰变的预测和维修时机、策略的选择,并对两种不同结构类型的沥青路面进行了实例分析。本文的研究可以为当前新形势下的公路建设项目投资决策和运营管理提供参考。     

城市道路维修与养护

针对城市道路的维修与养护,一方面从道路缺陷部位进行改进,另一方面要注重养护工作的科学性和管理的规范性。文章分析了城市道路养护的重难点,同时探讨了健全的道路管理维修制度,旨在促进城市道路的顺畅运行。     

谈邢临高速公路路面养护管理

邢临高速自从运行以来一直十分注重路面养护和管理问题,随着与山东高邢高速和山西邢汾高速的连接,车流量的增加,路面养护和管理问题已经成为工作中的重中之重。论文结合邢临高速公路日常养护管理的经验,提出了一些看法,与广大高速研究者一起探讨。     

城市市政道路的维修与养护

随着经济的发展,道路交通变得越来越发达。为保通行安全,道路的养护工作也变得越来越重要。对此要利用科学的手段和正确的方法做好市政道路的养护工作,尽量延长道路的使用寿命。本文主要对此问题进行了探讨。     

城镇住宅价值指标体系构建

从价值工程的基本原理来界定住宅价值,住宅价值是住宅所实现的功能与成本之比。按照功能的载体对象的不同,文章将住宅的功能分为居室功能、社区功能、区位功能、环境功能等四大类;然后从消费者的角度出发,将住宅生命周期成本分为取得成本、使用成本、管理成本、维护成本、交通成本等五大类。最后,构建了具体的评价指标体系并给出了相应的评价内容以供参考。     

浅谈公路养护策略

针对公路养护工作在公路营运管理中的重要性,结合工作经验,就公路养护中常见的问题作了简单概括,并从四方面着手探讨了公路养护技术与策略,从而保证公路具有快速、畅通、安全、舒适、经济的使用功能。     

屏蔽门系统的全寿命周期成本管理与分析

屏蔽门系统近年来在轨道交通领域得到广泛应用。以10个车站的具体数据为例,从投资、运行和维护等方面,分析了屏蔽门系统设备全寿命成本的影响因素,并提出了一系列合理、可行的处理措施,以降低成本和提高成本管理效率。     

城市轨道交通车辆全寿命周期成本分析

城市轨道交通已经成为现代城市交通体系的重要组成部分,并且正在逐渐融入我国的各个大中城市。车辆是城市轨道交通工程中的核心组成部分。目前城市轨道交通车辆采购招标比选时,仅仅考虑车辆采购价格,并不包括车辆全寿命周期各个阶段发生的成本,因此做出的决策只是局部最优,并不是整体最佳。论文对城市轨道交通车辆全寿命周期的阶段进行划分,并对城市轨道交通车辆全寿命周期成本进行了成本分解,在此基础上构建了城市轨道交通车辆全寿命周期成本模型。最后将城市轨道交通车辆全寿命周期成本模型应用于地铁A型车辆进行实例分析,得出结论为:车辆购置成本占车辆全寿命周期成本的51.68%,所以进行城市轨道交通车辆选型时应从车辆的全寿命周期出发。     

高速公路沥青路面预防性养护技术的探讨

针对我国目前高速公路养护现状,从高速公路沥青路面预防性养护的概念入手,分别从养护措施适用性、养护标准和全寿命周期等方面进行分析评价,并对预防性养护的未来发展趋势这一热点问题进行了探讨,从而延长路面使用寿命,保证道路行车质量和行车安全。     

A multi-objective optimisation approach for sustainable pavement management

Addressing the multidimensional challenges involved in advancing the sustainability of pavement systems requires the development of optimisation-based decision support system (DSS) for pavement management with the capability to identify optimally sustainable pavement maintenance and rehabilitations (M&R) strategies. The main objective of this research work is to develop a multi-objective optimisation framework that hosts a comprehensive and integrated pavement life cycle costs–life cycle assessment model that covers the pavement’s whole life cycle, from the extraction and production of materials to construction and maintenance, transportation of materials, work-zone traffic management, usage and end-of-life. The capability of the proposed DSS is analysed in a case study aiming at investigating, from a full life cycle perspective, the extent to which a number of pavement engineering solutions are efficient in improving the environmental and economic aspects of pavement sustainability, when applied in the management of a road pavement section. Multiple bi-objective optimisation analyses considering accordingly agency costs, user costs and greenhouse gas emissions were conducted based on a multi-objective genetic algorithm. Pareto fronts were obtained for each analysis, originating a set of non-dominated maintenance and rehabilitation solutions. Posteriorly, a multi-criteria decision analysis method was used to find the best compromise solution for pavement management.     

西安实施公共汽车专用道(路)的可行性初探

公共汽车专用道（路）是一种速度较快、运送能力较大、建设周期短、投资省、见效快的公共客运道路，也是一种从常规公共交通过渡到快速轨道交通的中间形式。特别在西安市还不具备大量投资修建快速轨道交通的经济能力之前，公共汽车专用道是解决西安市公共汽车运营速度低、车辆拥挤的好办法之一，西安市在道路及管理方面有其自己的优势，应该利用这种优势，尽早修建西安市的公共汽车专用道（路）。     

城市地下综合管廊定价模型及实证研究

在分析我国已建成的部分城市地下综合管廊没有充分发挥预期效果的原因的基础上,为了吸引投资和促进综合管廊的发展,笔者首先针对已有定价模型的不足,根据“谁受益,谁付费”的原则,通过专家调查和文献分析,确定了管线横截面积、管线年度经营收益、节约的管线建设成本、节约的管线维护成本和管理难度5个分摊因素。进而根据入廊费和年运营维护费确定各因素的重要程度,区分入廊费用分摊因子和年运营维护费用分摊因子,构建了一个更公平合理的定价模型。最后通过实证分析,得出各入廊管线单位负担费用均低于传统直埋方式产生费用的结论,且费用分摊更为合理,说明模型的实用性较强,对我国城市地下综合管廊的建设和发展有一定的参考价值。     

省县道公路状况评价研究

以永丰县公路为例，评价分析了省县道公路的路面状况特点，指出省县道公路交通量、路面行驶质量、路面破损状况与具体路段使用情况密切相关，在应用预防养护措施时应结合具体情况综合评价分析。     

挪威海底公路隧道经验——施工、运行、费用和维护

根据2002年关于挪威海底公路隧道的一论文集(挪威公路管理局公路技术部编辑,题目为"论文集98——挪威海底公路隧道",将详细阐述挪威海底隧道的施工建造等经验。挪威第一条海底公路隧道是在1983年通车的,随后建成了另外24条海底公路隧道,至今共有25条海底公路隧道建成通车,总长度达100km。几条新的海底公路隧道目前正在建设中,还有几条则在规划当中,其中最长将达24km。大多数条海底公路隧道是单洞双线,但是当坡度大于6%时,有些隧道就增加一条线。海底公路隧道都位于沿海岸线的干线公路上,以代替原有的繁忙的轮渡,并建立大陆与当地之间的无轮渡连接。据此,主要介绍这些隧道工程中得到的经验,总的来说,海底公路隧道的建设费用逐渐降低,但是各工程间差异很大,各个隧道的运行和维护的费用也相差悬殊,再投资和设备花费也特别高。经验表明,随着渗水量逐年减少,因而抽出渗透水的要求也降低了。介绍了1996年前17条海底隧道中发生的事故和火灾,对19起造成人身伤害的事故进行了分析。其事故发生率极低,只有0.09(每年每一百万车辆每公里发生的事故次数),最高的事发率是在陡坡的年平均日通车量(AADT)低于1500的隧道中。挪威海底隧道中只发生过3起火灾事故,低于交通事故率10%,而这项研究只包括了17条隧道中发生的19起事故。     

新疆公路养护机械使用现状及发展对策研究

通过对新疆公路各养护段的调研,总结了目前公路养护机械的维护和管理存在的问题,从体制改革、技术管理、养护机械化等方面对新疆高等级公路养护管理发展提出合理化建议和对策,解决了公路养护行业的实际问题。     

Optimal allocation of area in hierarchical road networks

This paper deals with the hierarchical road network design using a continuous model. The model is based on a grid road network where roads are classified into three types: access roads, minor arterial roads, and major arterial roads. Using a continuous approximation in which the distance is measured as the rectilinear distance, we obtain a simple approximation for the total travel time. We then find the optimal allocation of area taken up by roads at each level of the hierarchy so as to minimize the sum of the travel and construction costs. The result demonstrates how the total traffic volume, the traffic composition, and the unit construction cost affect the optimal road area. The optimal area of major arterial roads increases with the total traffic volume and the proportions of inward, outward, and through traffic and decreases with the unit construction cost.