Image-based 3D reconstruction using traditional and UAV datasets for analysis of road pavement distress

On local and urban networks, the enduring issue of scarce resources for Maintenance, Rehabilitation, and Reconstruction strategies (MR&R) has led, in many cases, to using unadjusted or poor techniques for road pavement distress detection and analysis, yielding ineffective or even counterproductive results. Therefore, it is necessary to have tools that can carry out quick, reliable and low-cost assessment surveys. This paper aims at validating the use of innovative and low-cost technologies for road pavement analysis, assessing their potentialities for improving the automation and reliability of distress detection. A Structure from Motion (SfM) technique is analyzed at different altitudes. The technique was applied on a distressed road pavement inside the University Campus in Palermo. The models obtained were compared with a terrestrial laser scanned 3D model to analyze the technique's metric accuracy and reliability. The results have shown that the technique accurately replicates pavement distresses, inciting an integrated approach to optimize pavement management strategies.     

Image‐based crack assessment of bridge piers using unmanned aerial vehicles and three‐dimensional scene reconstruction

Crack assessment of bridge piers using unmanned aerial vehicles (UAVs) eliminates unsafe factors of manual inspection and provides a potential way for the maintenance of transportation infrastructures. However, the implementation of UAV‐based crack assessment for real bridge piers is hindered by several key issues, including the following: (a) both perspective distortion and the geometry distortion by nonflat structural surfaces usually appear on crack images taken by the UAV system from the pier surface; however, these two kinds of distortions are difficult to correct at the same time; and (b) the crack image taken by a close‐range inspection flight UAV system is partially imaged, containing only a small part of the entire surface of the pier, and thereby hinders crack localization. In this paper, a new image‐based crack assessment methodology for bridge piers using UAV and three‐dimensional (3D) scene reconstruction is proposed. First, the data acquisition of UAV‐based crack assessment is discussed, and the UAV flight path and photography strategy for bridge pier assessment are proposed. Second, image‐based crack detection and 3D reconstruction are conducted to obtain crack width feature pair sequences and 3D surface models, respectively. Third, a new method of projecting cracks onto a meshed 3D surface triangular model is proposed, which can correct both the perspective distortion and geometry distortion by nonflat structural surfaces, and realize the crack localization. Field test investigations of crack assessment of a real bridge pier using a UAV are carried out for illustration, validation, and error analysis of the proposed methodology.     

Alternative modeling framework for pervious concrete pavement condition analysis

Pervious concrete pavement (PCP) is listed as one of the best stormwater management practices by the Environmental Protection Agency (EPA) due to its capacity to reduce impervious areas, capability to improve water quality, reduce runoff quantity, eliminate the need for detention basins, protect downstream channels, and reduce flooding (save lives and properties). Moreover, it is designated a “Green Asset” since it allows stormwater to seep through pavement to recharge ground water level. PCP may potentially improve skid resistance, reduce noise, decrease heat, and reduce water contamination. However, since PCP must have adequate permeability (porous structure), it can potentially be susceptible to freeze–thaw damage particularly in cold climates. To deploy the PCP in a transportation network, its performance should be thoroughly evaluated. For this purpose, the condition of PCP has to be defined and determined over time. Since PCP has not been widely investigated in cold climates such as Canada, no condition indices have been defined for it. This paper proposes a combined condition index for PCP to ensure that it will perform adequately over time. To develop a combined condition index, both a panel rating approach and objective measurements are employed to assess surface distresses and permeability rates of specific PCP sections. The panel rating method is applied due to the lack of long-term performance data to evaluate PCP sections’ conditions with regards to surface distress (e.g., raveling, spalling, and cracking) and functional performance (i.e., permeability rate). The objective measurements of surface distress and permeability rate (functional performance) of the same PCP sections are performed through the application of the adjusted Ministry of Transportation of Ontario (MTO) protocol and a permeameter, respectively. Regression analysis is used to relate surface objective measurements to the surface panel rating. As a result of statistical analyses, the panel rating method is successfully applied only in surface distress rating. Accordingly, a combined condition index is developed using surface distress ratings and objective functional performance measures.     

Spatiotemporal matching method for tracking pavement distress using high-frequency detection data

Various algorithms based on deep learning have achieved promising results in pavement distress detection. However, the detected distresses are not tracked throughout the life cycle. In long-term application scenarios, pavement distresses may take on different forms due to image acquisition mode, distress development, and environmental change, which make tracking distresses a tough question. We present in this study a spatiotemporal matching method based on high-frequency real pavement distress datasets. Pavement distresses of fixed routes were collected 30 times over 5 months, and distresses with spatiotemporal information were obtained at time series. We apply image rectification, stitching and distress class, and bounding box generation algorithms for pre-processing to align the collected images to the same-detail level and angle. A four-step spatiotemporal matching module is designed, including global positioning system (GPS) filtering, class filtering, relative position filtering, and distress feature filtering. The results reveal that the comprehensive rank-3 hit rate of the matching method reaches 88.73%, and the method is robust to environmental factors, which helps show performance decay of distresses and the effect of maintenance operations. It is concluded that the spatiotemporal matching method is convenient to operate, and it lays the foundation for an agency to track distress evolution and make timely treatment of distresses in the life cycle.     

A Pavement Crack Detection Method Combining 2D with 3D Information Based on Dempster‐Shafer Theory

Pavement cracking is one of the main distresses presented in the road surface. Objective and accurate detection or evaluation for these cracks is an important task in the pavement maintenance and management. In this work, a new pavement crack detection method is proposed by combining two‐dimensional (2D) gray‐scale images and three‐dimensional (3D) laser scanning data based on Dempster‐Shafer (D‐S) theory. In this proposed method, 2D gray‐scale image and 3D laser scanning data are modeled as a mass function in evidence theory, and 2D and 3D detection results for pavement cracks are fused at decision‐making level. The experimental results show that the proposed method takes advantage of the respective merits of 2D images and 3D laser scanning data and therefore improves the pavement crack detection accuracy and reduces recognition error rate compared to 2D image intensity‐based methods.     

关于现代城市公共交通系统的思考

我国城市中的公共交通存在路线过于集中、主次不分、服务质量低下、缺少公交换乘枢纽等问题,应正确认识"优先发展公共交通"的基本国策,正确理解城市公共交通和城市发展形态、城市用地布局结构及城市道路系统的关系,正确处理公共交通线路和城市道路与城市用地的关系,建设公交换乘枢纽以提高公共交通效率和服务性.在一般情况下,库尔蒂巴概念的"BRT"既不适合于我国城市常见的双向、高强度的发展模式,也不是解决我国城市公共交通问题的灵丹妙药.     

江苏省农村公路设计参数的拟定

通过对江苏省农村公路交通量与交通特征的调查,利用国内对于低交通量道路的研究成果,考虑了农村公路的特点,确定了江苏省农村公路设计交通量,并结合典型结构所作的参数敏感性分析,确定了江苏省农村公路老路补强标准,并以此为基础给出地基分级标准。     

Patch detection for pavement assessment

Pavement management systems rely on comprehensive up-to-date road condition data to provide effective decision support for short, medium and long term maintenance scheduling. However, the cost per mile of the existing condition data collection methods allows only for periodical surveys. This leads to long gaps between inspections and a focus on major roads over rural ones. Therefore, pavement condition monitoring systems that provide inexpensive frequent updates on the road condition are necessary. Such systems would require robust and automatic defect detection methods using low-cost sensors. In this paper, one such method is proposed for detecting road patches from video data acquired by the car's parking camera. A patch is initially detected based on its visual characteristics, which are: 1) it consists of a closed contour and 2) its texture is the same with the surrounding intact pavement. The patch is then passed to a kernel tracker in order to trace it in subsequent video frames. This way redetection is avoided and each patch is reported only once. The method was implemented in a C# prototype and tested with video data consisting of approximately 4000 frames collected from roads in Cambridge, UK. The results show that the suggested method has 84% precision and 96% recall.     

城市道路改扩建过程中防治反射裂缝措施分析

随着城市道路的升级改造,路面结构会产生某些病害,譬如反射裂缝,对交通运输影响较大。本文将在了解城市道路改扩建过程中反射裂缝形成机理的基础上,从各个角度探讨反射裂缝防治的具体措施,为提高城市路面耐久性提供参考。     

长江三峡库区移民城市发展与道路交通建设的互动关系

长江三峡工程促进了库区移民城市的快速发展,区域与城市道路交通的建设发挥了重要作用。文章通过分析移民城市道路建设的主要影响因素,以及与城市协调发展中存在的问题,从山地城市特征、内外交通衔接及道路建设的技术措施等方面,总结移民城市建设与道路交通的互动关系。     

A Computational Methodology for Assessing the Time‐Dependent Structural Performance of Electric Road Infrastructures

An infrastructure adapted to dynamic wireless recharging of electric vehicles is often referred to generically as Electric Road (“e‐road”). E‐roads are deemed to become essential components of future grid environments and smart city strategies. Several technologies already exist that propose different ways to integrate dynamic inductive charging systems within the infrastructure. One e‐road solution uses a very thin rail with box‐section made of fibre‐reinforced polymer, inside which an electric current flows producing a magnetic field. In spite of the great interest and research generated by recharging technologies, the structural problems of e‐roads, including vibrations and structural integrity in the short and/or long period, have received relatively little attention to date. This article presents a novel computational methodology for assessing the time‐dependent structural performance of e‐roads, including a recursive strategy for the estimation of the lifetime of surface layers. The article also reports some numerical findings about e‐roads that will drive further numerical analyses and experimental studies on this novel type of infrastructure. Finally, numerical simulations have been conducted to compare an e‐road with a traditional road (“t‐road”), in terms of static, dynamic and fatigue behavior.     

Analysis of cost effective pavement treatment and budget optimization for arterial roads in the city of Chattanooga

Many transportation agencies lack sufficient funds to maintain and repair roads, which results into increased pavement maintenance cost. Pavement Management System (PMS) has demonstrated to be an essential tool for proper management of infrastructure and proper utilization of available funds. The University of Tennessee at Chattanooga utilized Micropaver software as PMS tool to conduct a pavement management analysis of principal arterials in the City of Chattanooga. The study used the City of Chattanooga pavement database to create the current and future pavement conditions. Maintenance and repair (M&R) planning analysis was also performed in order to determine the most cost-effective treatment and suggest the optimum utilization of funds for the city. An analysis of five budget scenarios was conducted for a five-year plan using the critical pavement condition index (PCI) method (ASTM D6433). Results show that the backlog elimination budget would be the best scenario because it increases the pavement condition and eliminates the backlog of major maintenance and repairs over the five-year period. The unlimited budget seems though ideal, it does not improve pavement condition. Maintaining current condition and limited budget scenarios would increase both the backlog and the total cost of maintenance and repairs over the analysis period.     

台北市交通建设管理对重庆的启示

该文简要介绍了台北市概况及交通政策,并通过对台北市公共交通、停车管理、道路交叉口"渠化"与"干道绿波"、占道开挖管理、人行过街设施优化、道路收费政策等方面的研究,对比分析重庆市与台北市的交通承载能力,得出重庆市的道路交通承载能力还有大幅度提升余地的结论,提出当前解决交通拥堵的状况应由修建城市道路转移到改善管理手段上来。最后建议通过大力发展公共交通、增加路网密度、优化交叉口、发展单向交通组织加强智能交通系统建设等方式来提高重庆交通的管理水平与服务水平     

黄土台塬区农村道路生态化模式建构 及设计应对探究——以宝鸡市金台区北坡 路域生态整治为例

农村道路生态化研究对统筹推进中国农村人居环境整治工作、维育区域生态格局乃至实施乡村振兴战略具有重要意义。针对当前中国黄土台塬区农村道路建设过程中景观割裂、环境侵扰和水土流失等问题,基于国内外道路生态学的理论和实践,梳理农村道路环境及景观研究进展,厘清其景观生态化内涵机理,从道路主体、沿线设施、路域环境、养护管理等多维度构建黄土台塬区农村道路景观生态化改造模式。以宝鸡市金台区北坡生态整治项目作为实证案例,总结梳理美丽农村路绿色化营建方法举措,通过生态修复、景观重构、文化塑造和工程建设等手段推进黄土台塬区农村路域景观生态的修复与重塑,为营建美丽绿色农村路、助力乡村振兴战略提供技术支撑。     

Integration of geographic information systems and computer vision systems for pavement distress classification

The main objective of this research work was to investigate the potential of integration of geographic information system (GIS), global positioning system (GPS) and computer vision system (CVS) for the purpose of flexible pavement distresses classifications and maintenance priorities. The classification process included distress type, distress severity level and options for repair. A system scheme that integrated the above-mentioned systems was developed. The system utilized the data collected by GPS and a PC-based vision system in a GIS environment. GIS Arcview software was used for the purpose of data display, query, manipulation and analysis.The developed system provided a safer pavement condition data collection technique, flexible data storage, archiving, updating and maintenance priorities updating. Maintenance priorities were assigned based on priority indices values computed by priority index (PI) or available budget criterion. This technique was cost-effective and offered wise-based decision making for different maintenance activities and programs.Using average daily traffic (ADT), distance from maintenance unit (R), pavement section area and pavement age, statistical models were developed to forecast pavement distress quantities. It was found that ADT and pavement age variables were the most significant factors in the distresses quantification.     

Efficiency measurement of the maintenance of paved lanes using data envelopment analysis

While the road maintenance performance measurement systems that are currently in use investigate maintenance level of service (i.e. effectiveness of the road maintenance), the fundamental relationship between the maintenance level of service and the budget requirements (i.e. the efficiency of road maintenance) has not received as much attention. Given that not knowing how ‘efficient’ transportation agencies are in being ‘effective’ can lead to excessive and unrealistic maintenance budget expectations, there is a need for a performance measurement system that can assess the overall efficiency of road maintenance operations. To address this need, a framework was developed and implemented to assess the relative cost efficiency of eight counties in Virginia, USA in maintaining the paved lanes of the Interstate roads. Such framework is developed using a methodology known as data envelopment analysis which is based on the production theory and principles of linear programming. The results indicate that the Rockbridge County is the most efficient and the Roanoke County is the least efficient in maintaining the paved lanes. The findings of this research are intended to be used as guides for benchmarking as well as managerial actions and policy making for decision making with respect to road maintenance.     

Semiautomatic Extraction of Road Horizontal Alignment from a Mobile LiDAR System

This article proposes a method to semiautomatically extract the road axis through a mobile LiDAR system, a recent popular technology for transportation‐related applications, road estimation and even to enhance driver safety. In particular, the approach developed has two components: (1) the feature extraction from LiDAR data to model the road axis, and (2) the estimation of the horizontal alignment that meets the requirements and practice for a transportation authority. Given the massive and complex character of the data captured by the system, a hierarchical (coarse‐to‐fine) and robust strategy based on segmentation, parameterization and filtering, which determine the road centerline together with the geometric elements that compose its horizontal alignment, such as straight lines, circular arcs, and clothoids, has been developed and implemented. Test results using a simulated and a real data are discussed and validated. The experimental results obtained with real cases guarantying relative accuracies under 2%, being a useful approach to produce accurate estimations of the horizontal geometric features of the road alignment.     

沥青路面开裂破坏及防治措施

改革开放以来,我国的公路交通建设迅速发展,修建了大量的高等级公路,尤其是近几年,铺筑了大量的高等级沥青路面,但也应看到,不少沥青路面出现了各种病害,早期损伤相当严重,本文简要介绍了沥青路面主要常见病害之一的路面开裂问题,并提出了一些防治措施。     

Fuzzy Representation of Pavement Condition for Efficient Pavement Management

Abstract: Many government agencies and private consulting companies manage large pavement networks in terms of infrastructure condition assessment and maintenance planning. Efficient pavement management is supported by pavement management systems (PMSs), which includes models for pavement condition assessments considered “valuable” by agency's engineers. The objective of this article is to define a pavement condition model able to overcome surveyors’ subjectivity in rating distresses and thus provide meaningful pavement conditions for the agencies to employ in project planning. The article proposes a fuzzy inference model for calculating pavement condition ratio (PCR) specifically tailored on the Alabama Department of Transportation Pavement (ALDOT) guidelines and policies. Applied to several surveyors’ ratings, the proposed model has the ability to smooth distress extent differences among surveyors producing PCR values within acceptable range of variability. The proposed approach has the intention of not only enhancing pavement condition characterization but also to exploit the opportunity made available by automation in the collection and interpretation of pavement data which are anyway characterized by an inherent subjectivity.     

Life cycle cost considerations in project appraisals of collision-free roads

In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.