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5 CHAPTER ONE INTRODUCTION This chapter introduces the basic problem associated with the use of spatial data management and analysis procedures for pavement management. It also presents the objective, scope, and organization of the synthesis report. BACKGROUND Pavement management systems (PMSs) have become stan- dard tools in most state departments of transportation (DOTs). Highway agencies have realized the benefits of having a decision support system (DSS) that assists them in finding cost-effective strategies for managing their pavement networks (1). Furthermore, there is a trend to- ward the development of management systems for other transportation assets and the integration of the decision support tools in comprehensive asset management systems. This trend was furthered by the Intermodal Surface Trans- portation Efficiency Act (ISTEA) of 1991 (2), which re- quired state DOTs to develop several management systems that had to be integrated with one another to a certain de- gree. Although some of the penalties associated with this mandate were later removed, many DOTs realized the ad- vantages of such an approach and continued the efforts to- ward developing the management systems and integrating them in agency-wide asset management systems. Further- more, the Governmental Accounting Standards Board Statement 34: Basic Financial Statementsâand Manage- mentâs Discussion and Analysisâfor State and Local Gov- ernments, reenergized this trend by specifying that full ac- crual accounting principles be used for government-wide statements. This standard allows agencies to use a modi- fied or preservation approach that does not depreciate physical assets (e.g., roads and bridges) that are maintained at a level predefined by the government. However, to use this reporting method, agencies must have in place appro- priate asset inventory, condition assessment and monitor- ing, and preservation procedures that are characteristic of pavement and asset management systems (3). Pavement and asset management systems are supported by collecting and retaining a tremendous amount of infor- mation associated with the nationwide network of high- ways. Agencies collect and store data from a variety of sources, such as historical records, surveys, and auto- mated data collection vehicles. A PMS uses road inven- tory, pavement condition, traffic, and construction and maintenance history data that are not always collected by the same office within the organization. These data are normally available in a wide variety of formats, spatial and database referencing systems, and media. Examples include drawings, pictures, maps, text descriptions, ta- bles, video, and experience. Integrating data to support decision making requires that the data be stored by us- ing consistent indexing, location referencing systems, and data definitions or that appropriate transformations be de- veloped. Transportation agencies must organize the data available for pavement and asset decisions into forms suitable for many applications at the different levels of decision mak- ing within the agency. Examples include investment trade- offs among different asset types; highway monitoring and management; development of construction, maintenance, and rehabilitation programs; and design and analysis of specific projects. Consequently, there is a demand for effi- cient tools for integrating, managing, and analyzing that in- formation. Spatial technologies, such as Geographic Information Systems (GIS), are particularly appropriate for integrating highway data and enhancing the use and presentation of these data for highway management and operation by using spatial relationships to relate geographic and geometric ob- jects and events. To different degrees, highway manage- ment problems, such as pavement management, involve re- lations between objects and events located in different spatial positions. Road networks extend over a wide area and interact with various land elements, including rivers, mountains, buildings, and other roads. Because the data used in the decision-making process have spatial compo- nents, the use of spatial technologies emerges as a very ap- pealing alternative. Spatial technologies may enhance the analysis of several transportation-related issues and may improve the quality of the decision-making process. SYNTHESIS OBJECTIVE AND SCOPE There are a number of states that have developed, or are developing, spatial applications for pavement management. The objective of this synthesis is to systematically docu- ment the state of the practice and knowledge of pavement management applications using GIS and other spatial tech- nologies. The main points addressed include the identifica- tion of best practices, potential future applications, and the spatial analysis features that are needed for developing more powerful and effective PMS applications.
6 Synthesis Scope Although this synthesis discusses issues regarding the use of different spatial referencing methods, its focus is on the application of GIS in pavement management. It includes information from a number of sources, including a litera- ture review, an electronic survey of state practices, and fol- low-up telephone interviews with a select number of state transportation agencies. The survey was conducted elec- tronically using an interactive web-based survey developed by the Kansas DOT (KDOT). A link to the electronic sur- vey was sent to the pavement management contacts and GIS-T (GIS for Transportation) representatives in all 50 states as well as some Canadian provinces. The surveyed individuals were asked to go to a web page where an elec- tronic questionnaire was displayed. This questionnaire was dynamic and the questions displayed were dependent on the previous responses. Once the user pressed the submit button, the survey was automatically saved in a database and a âspecial linkâ was e-mailed to the respondent. This link allowed the respondent to return to the response and review, complement, or modify the submitted information. After the survey stop date, KDOT PMS personnel im- ported the responses into an MS Excel spreadsheet and transmitted it to the consultants. The electronic survey proved very effective, with a total of 73 responses from 48 states and 4 Canadian provinces received. Many respondents indicated that the web-based format made it very easy to respond to and submit the questionnaire. For the purpose of the statistical analysis, and to avoid double counting, only one response per state was considered. In a few cases, the responses from the PMS and GIS-T representatives did not agree. These in- consistencies showed that, in several DOTs, the GIS- related activities are perceived differently by the two groups and that there is a possible communication problem between the PMS and GIS units, as will be discussed fur- ther in chapter two. The differences were resolved through follow-up telephone interviews. The PMS contact response was used when available, except for the sections that dealt with system integration and software use. Report Organization Chapter two includes a brief introduction to PMS, GIS, and spatial analysis, and discusses how the technologies have been combined to enhance the highway management proc- ess. Chapter three covers the primary issues related to PMS data collection, management, and dissemination. The main sources of pavement management information are identi- fied. Issues pertaining to the type of data collected, data storage, methods of referencing, interaction with other management systems, data integration, and the handling of historical records are discussed. Examples of spatial appli- cation for PMS data integration are presented. Chapter four presents some of the main applications of spatial technologies for map generation and PMS spatial analysis. Chapter five covers the approaches used for integrating PMS and GIS, the different GIS tools used to support pavement management decisions, and other implementa- tion-related issues. The level of satisfaction, advantages, problems, and solutions are discussed. Chapter six summarizes the main findings of the re- search and the major conclusion of the synthesis study. This chapter also provides some recommendations for fu- ture research needs.
