Using GIS, Genetic Algorithms, and Visualization in Highway Development

A model for highway development is presented, which uses geographic information systems (GIS), genetic algorithms (GA), and computer visualization (CV). GIS serves as a repository of geographic information and enables spatial manipulations and database management. GAs are used to optimize highway alignments in a complex search space. CV is a technique used to convey the characteristics of alternative solutions, which can be the basis of decisions. The proposed model implements GIS and GA to find an optimized alignment based on the minimization of highway costs. CV is implemented to investigate the effects of intangible parameters, such as unusual land and environmental characteristics not considered in optimization. Constrained optimization using GAs may be performed at subsequent stages if necessary using feedback received from CVs. Implementation of the model in a real highway project from Maryland indicates that integration of GIS, GAs, and CV greatly enhances the highway development process.     

Optimizing Design of Highway Horizontal Alignments: New Substantive Safety Approach

Abstract:   Highway agencies are continually facing safety problems on highways, especially on horizontal alignments. Traditionally, the geometric design implicitly considers safety through satisfying minimum design requirements for different geometric elements. This article presents a new substantive-safety approach for the design of horizontal alignments based not only on minimum design guidelines, but also on actual collision experience. The curve radii, spiral lengths, lane width, shoulder width, and tangent lengths are determined to optimize the mean collision frequency along the highway. The model allows the parameters of the horizontal alignment to vary within specified ranges. The model also considers any specified physical obstructions in selecting the optimal alignment. Collision experience is addressed using existing collision prediction models for horizontal alignments and cross sections. The model is applicable to two-lane rural highways for which collision prediction models exist. Application of the model is presented using numerical examples. The proposed substantive-safety approach takes horizontal alignment design one step further beyond the minimum-guideline concept, and therefore should be of interest to highway designers.     

A modified motion planning algorithm for horizontal highway alignment development

A horizontal alignment can be represented by three key factors: number of horizontal points of intersection (HPIs), their locations, and corresponding horizontal curve radii. Deciding all the three factors simultaneously requires extensive effort, which is not practically feasible in the manual alignment development process. Most available computer‐aided methods prioritize some or all the three factors in the automated alignment development processes. However, approximation in HPI location or pre‐selection of HPI number and curve radius are the few limitations of these methods. This study presents a modified motion‐planning based algorithm for developing new horizontal alignments with optimized costs and impacts. It simultaneously uses a low‐discrepancy sampling technique to develop increasingly dense potential HPIs, rapidly exploring random trees to find a suitable number of intermediate HPIs at appropriate locations and sequential quadratic algorithm to select optimally fitted curve radii. The proposed algorithm is integrated with the GIS database for realistic location‐dependent cost and environmental impact assessment. Two real‐world study areas were selected to compare the results with the one reported in the literature and to evaluate backtracking capability. Results indicated the proficiency of the proposed algorithm in developing new alignments. The sensitivity analyses revealed the effect of design speed and right‐of‐way width on the alignment generation. The proposed algorithm can automate the new horizontal highway alignment development process and support highway engineers in planning and development.     

Intersection Modeling for Highway Alignment Optimization

Abstract:   When optimizing a highway alignment, it is desirable to consider new and modified intersections along it. This article develops methods for locally optimizing intersections within highway alignment optimization processes. Design and operational characteristics for intersections are reviewed from the literature. The formulation considers the major costs that are sensitive to intersection characteristics. Genetic algorithms are used for optimal search. The proposed methods are implemented on an artificial study area and on a real one through the use of geographic information systems. The results show how the methods work for local optimization of intersections as well as for optimizing entire alignments. These methods can be used for improving search flexibility, thus allowing more effective intersections. They also provide a basis for extending the alignment optimization from single highways to networks .     

A Customized Particle Swarm Method to Solve Highway Alignment Optimization Problem

Abstract: Optimizing highway alignment requires a versatile set of cost functions and an efficient search method to achieve the best design. Because of numerous highway design considerations, this issue is classified as a constrained problem. Moreover, because of the infinite number of possible solutions for the problem and the continuous search space, highway alignment optimization is a complex problem. In this study, a customized particle swarm optimization algorithm was used to search for a near‐optimal highway alignment, which is a compound of several tangents, consisting of circular (for horizontal design) and parabolic (for vertical alignment) curves. The selected highway alignment should meet the constraints of highway design while minimizing total cost as the objective function. The model uses geographical information system (GIS) maps as an efficient and fast way to calculate right‐of‐way costs, earthwork costs, and any other spatial information and constraints that should be implemented in the design process. The efficiency of the algorithm was verified through a case study using an artificial map as the study region. Finally, we applied the algorithm to a real‐world example and the results were compared with the alignment found by traditional methods.     

Feasibility of Computer Visualization in Highway Development: A Fuzzy Logic-Based Approach

Abstract:   Building transportation infrastructure requires careful planning and design with due consideration to land and environmental impacts. Imprecise assessments of detailed design requirements, and land and environmental impacts lead to frequent scope changes of transportation infrastructure improvement projects. Computer visualization (CV) and geographic information systems (GIS) can greatly assist in understanding the detailed design requirements as well as land and environmental impacts. However, the application of CV is quite limited in transportation primarily because of the limited knowledge of its benefits over cost. This study investigates the feasibility of CV in modeling highway improvement sections. Two potential benefits are realized through the proposed modeling: (1) better representation of future improvements resulting in enhanced public and political support and (2) early identification of adverse environmental and land impacts as well as detail design requirements resulting in fewer scope changes. A fuzzy logic-based general approach is proposed to calculate the expected benefits of CV. A computer code called the Projection Option Processor (POP) is developed in Microstation's BASIC language to automate repetitive tasks in the visualization procedure. Two real highway projects from Maryland are visualized and the benefits and costs of the visualization are estimated using the proposed fuzzy logic-based approach. The results indicate that using POP is cost-effective resulting in higher benefit-cost ratios (B/C). Increasing the number of views, alternatives, and reevaluations for visualization may increase the total visualization cost significantly.     

Prescreening and Repairing in a Genetic Algorithm for Highway Alignment Optimization

Abstract:   The method of handling infeasible solutions in an evolutionary search algorithm [e.g., genetic algorithms (GAs)] is crucial to the effectiveness of the solution search process. This problem arises because solution search steps, techniques, and operators used in GAs (such as reproduction, mutation, and recombination) are normally  " blind " to the constraints, and thus GAs can generate solutions that do not satisfy the requirements of the problems. In GA-based highway alignment optimization (HAO), many infeasible solutions, which violate model constraints, are also possibly generated, and evaluation of such solutions is wasteful. This study focuses on ways to avoid wasting computation time on evaluating infeasible solutions generated from the GA-based HAO, and develops a prescreening and repairing (P&R) method for an efficient search of highway alignments. The key idea of the P&R method is to repair (before the very detailed alignment evaluation) any candidate alignments whose violations of design constraints can be fixed with reasonable modifications. However, infeasible alignments whose violations of constraints are too severe to repair are discarded (prescreened) before any detailed evaluation procedure is applied. The proposed P&R method is simple, but significantly improves computation time and solution quality in the GA-based HAO process. Such improvements are demonstrated with a test example for a real road project. Through the example study, it is shown that the model incorporating the P&R method can find a good solution much faster (by approximately 23%) than the model with the conventional penalty method. In addition, the P&R method allows the model to evaluate about 70% more solutions than that it can evaluate with the penalty method for the same number of generations.     

A deep reinforcement learning approach to mountain railway alignment optimization

The design and planning of railway alignments is the dominant task in railway construction. However, it is difficult to achieve self-learning and learning from human experience with manual as well as automated design methods. Also, many existing approaches require predefined numbers of horizontal points of intersection or vertical points of intersection as input. To address these issues, this study employs deep reinforcement learning (DRL) to optimize mountainous railway alignments with the goal of minimizing construction costs. First, in the DRL model, the state of the railway alignment optimization environment is determined, and the action and reward function of the optimization agent are defined along with the corresponding alignment constraints. Second, we integrate a recent DRL algorithm called the deep deterministic policy gradient with optional human experience to obtain the final optimized railway alignment, and the influence of human experience is demonstrated through a sensitivity analysis. Finally, this methodology is applied to a real-world case study in a mountainous region, and the results verify that the DRL approach used here can automatically explore and optimize the railway alignment, decreasing the construction cost by 17.65% and 7.98%, compared with the manual alignment and with the results of a method based on the distance transform, respectively, while satisfying various alignment constraints.     

道路线形对双车道公路通行能力的影响研究

双车道公路在选线时,由于平、纵线形指标选取的范围较大,它们之间的组合导致了双车道公路线形差异较大,通行能力也不尽相同。因此,平纵线形是影响双车道公路通行能力的主要因素。根据实测数据和已有研究,认为半径大于400m的平曲线和坡度小于3%的纵坡不影响道路的通行能力。定义有效曲度和有效梯度2个概念来分别表示平曲线的弯曲程度和竖曲线的陡峭程度,给出计算方法,并探讨其有关性质。根据仿真结果和速度差原则分别将有效曲度和有效梯度分为了7级和6级,将有效曲度和有效梯度进行组合,构造出42组不同道路线形下的双车道公路,在进行的仿真实验中,得到了相应的小客车速度-流量、流量-跟车率关系,最终得出不同道路线形条件下的双车道公路通行能力值。     

A 3D Model for Optimizing Infrastructure Costs in Road Design

In this article, the optimal design of a road joining two terminals is investigated. A geometric model is proposed including horizontal transition curves and vertical curves, obtaining parameterizations for the central axis of the road as well as for its entire surface. These parameterizations allow to express and compute, with great simplicity, the major infrastructure costs, including land acquisition, clearance, pavement, maintenance, and earthwork, where multiple layers of materials with different costs can be handled. The road design problem is formulated as a smooth constrained optimization problem and a two‐stage algorithm is suggested for its numerical resolution. Finally, numerical results are presented in an academic test and in a case study that propose designing a bypass in a Spanish national road (N‐640) to avoid crossing Monterroso's town center.     

基于时空大数据的公路工程信息化技术框架 ——以铺前跨海大桥为例

以空天地一体化为代表的时空大 数据结合了GIS、遥感、倾斜摄影、BIM和物 联网等技术,是公路信息化发展的重要动 力。本文阐述了由地理建模、地理设计、地理 监测及地理控制组成的时空大数据技术架 构,提出了地理信息、BIM和倾斜摄影等关 键技术,并介绍了基于BIM的公路信息化技 术在海南文昌铺前跨海大桥的设计和施工中 实际应用的经验和思考,揭示了将BIM和GIS 结合的技术应用于我国桥梁设计和施工领域 的优势,为以后进一步结合遥感、倾斜摄影 等先进技术,促进公路信息化技术和应用的 进一步发展奠定基础。     

Use of Heading Direction for Recreating the Horizontal Alignment of an Existing Road

This article proposes a new method for fitting the horizontal alignment of a road to a set of (x, y) points. Those points can be obtained from digital imagery or GPS‐data collection. Unlike current methods that represent road alignment through its curvature, the proposed method describes the horizontal alignment as a sequence of headings. An analytic–heuristic approach is introduced. The proposed method produces unique solutions even for complex horizontal alignments. Some examples and a case study are presented. This solution may not be accurate enough for road redesign, but it allows researchers and departments of transportation to obtain accurate geometric features.     

Multi-objective and probabilistic decision-making approaches to sustainable design and management of highway bridge decks

The aging and deterioration of highway bridges and the new requirements for sustainable infrastructures and communities require innovative approaches for their management that can achieve an adequate balance between social, economic and environmental sustainability. This paper presents a multi-objective decision-making approach for the sustainable design and management of highway bridge decks, which can consider several and conflicting objectives, such as the minimisation of owner's costs, users costs, and environmental impacts and uses goal setting and compromise programming to determine the satisficing and compromise solutions that yield the best trade-off between all competing objectives. The proposed approach is based on robust reliability-based mechanistic models of the deterioration and service life of reinforced concrete bridge decks, which include diffusion models for the prediction of chloride ingress into concrete and steel corrosion and thick-walled cylinder models for the prediction of stresses induced by the accumulating corrosion products in the concrete cover. The proposed approach is illustrated on the life cycle design and management of highway bridge decks using normal and high performance concrete. It is shown that the high performance concrete deck alternative is a Pareto optimum, while the normal concrete deck is found to be a dominated solution in terms of life cycle costs and environmental impacts.     

公路工程设计流程电算化的构想

详细考察了公路和城市道路勘测设计的具体实践 ,类比了公路工程设计的传统工作流程 ,并建立了公路工程设计流程的数学模型 ,提出公路工程设计流程电算化的构想     

山区高速公路线形设计

结合京承高速公路（苇子峪-京冀界段）工程的线形设计,从线形设计方法、平面线形设计、纵面线形设计、平纵线形组合设计和线形与环境的协调五个方面,就如何改进山区高速公路线形设计进行了分析研究,以期指导实践。     

高速公路路基加宽土工格栅加筋优化技术研究

基于分析高速公路改扩建工程新老路基间不协调变形的原因、控制技术方法及控制标准,对高速公路改扩建路基加宽土工格栅加筋优化技术进行了研究。以京港澳高速公路石家庄至磁县（冀豫界）段改扩建工程典型试验段为研究对象,建立了高速公路路基加宽有限元计算模型,分析了施工期路基填筑高度和竣工后15 a的地表附加沉降、附加水平位移和路面横坡比变化规律。采用土工格栅加筋新路基技术,通过改变土工格栅的弹性模量、加筋层数和加筋长度等技术参数,研究分析了土工格栅参数变化对路基表面沉降量及路面横坡比的影响。根据计算结果提出了高速公路路基加宽土工格栅加筋优化设计技术方案,该研究结果为高速公路改扩建土工格栅加筋路基设计提供了技术参考。     

Optimal Strategies for Highway Pavement Management in Developing Countries

Highway pavement design in developing countries is usually based on standards borrowed from industrialized countries. However, it may not be economically feasible to use these high design standards in developing countries, because of significant differences in socioeconomic conditions. Using the World Bank's highway design and maintenance standards model (HDM-III), this paper investigates optimal pavement design and its relationship with the developmental stage of a country. Optimal pavement design can be defined as that which minimizes total transport costs to society, which comprise the sum of agency costs and road user costs. Basic data for the analysis were derived from Chinese conditions, and appropriate adjustments were made to model five classes of hypothetical countries in different developmental stages. It is shown that the optimal trade-off between initial expenditure on construction and subsequent maintenance depends on the developmental stage of an economy. The same high design standards that are suitable for industrialized countries may not be economically justified in developing countries. Developing countries should start with modest pavements and then spend more on maintenance afterwards, which is an overdue, neglected priority today.     

Soft computing for solar radiation potential assessment in Algeria

ABSTRACT

Precise estimation of solar radiation is a highly required parameter for the design and assessment of solar energy applications. Over the past years, many machine learning techniques have been proposed in order to improve the forecasting performance using different input attributes. The aim of this study is the forecasting of one day ahead of horizontal global solar radiation using a set of meteorological and geographical inputs. In this respect, the Gaussian process regression methodology (GPR) and least-square support vector machine (LS-SVM) with different kernels are evaluated in order to select the most appropriate forecasting model. In order to assess the proposed models, the southern Algerian city, Ghardaia regions, was selected for this study. A historical data of five years (2013–2017) of meteorological data collected at Renewable Energies (URAER) in Ghardaia city are used. The achieved results demonstrate that all the proposed models give approximately similar results in terms of statistical indicators. In term of processing time, all the models showed acceptable computational efficiency with less computational costs of the GPR model among all machine learning models.     

公路隧道设计中相关问题的讨论

分析了公路隧道线形设计与平面线形设计的要点,探讨了公路隧道结构形式的选择策略及常用的结构形式在工程中出现的问题,并对公路的防排水设计方法进行了论述,为公路隧道设计积累了经验。     

System Dynamics (SD) -based concession pricing model for PPP highway projects

The design of concession price is essential to financial viability of Public–Private Partnership (PPP) highway projects. It is one of the most important variables that need to be determined during the negotiation period. However, there are few methods available for calculating the value of this variable. Research described in this paper aims to develop a reliable, objective, and systematic model for determining a rational concession price for PPP highway projects based on pro forma financial statements developed during the feasibility study period. The pricing parameters and price risk factors of PPP highway project were first identified and compiled through a comprehensive literature review. A concession pricing model using System Dynamics technique was then developed based on concession pricing parameters and the effectiveness of the proposed SD-based concession pricing model was verified by a real toll tunnel project located in China. The test result shows that the proposed model is reliable, accurate, and suitable for the application by practitioners for concession price determination. To overcome the effect of risk factors on concession price, a pricing adjustment model using Case-base Reasoning (CBR) technique was proposed to consider the unquantifiable risk factors. It is believed that a rational and practical concession pricing model can create a ‘win–win’ situation for both the private investor and the host government. This research framework can also be used as a reference to study other facilities' pricing models.