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39 5.1 Methodology This study developed a multicriteria methodology for prioritizing railroad grade crossings along a corridor for grade separation or other improvements. The methodology was implemented in a set of linked spreadsheets to develop the RCAT. The tool was developed on the basis of findings of this research, input from public and private transportation organizations, professional guidelines and reports, practical experience, and input from beta testers. The multicriteria methodology considers safety, economic, environmental, and community livability factors. For each of the selected crossings, a score for safety, economic, environ- mental, and community livability factors is computed. Then a final score, produced from a weighted average of the indi- vidual factor scores, is computed. The final score provides a prioritized list of grade crossings in the corridor. The tool can be used by state and local planners to prioritize grade crossings for separation or safety improvements along a corridor. The following section describes the information flow in the methodology and also briefly discusses the out- put obtained from this approach. More detailed description of RCAT is given in the user guide, presented in Appendix C [this appendix can be found online by searching the TRB web- site (www.TRB.org) for NCHRP Research Report 901: Priori- tization Procedure for Proposed RoadâRail Grade Separation Projects Along Specific Rail Corridors] Information Flow in the Methodology and the RCAT The information flow and the main steps involved in generating output from the RCAT are shown in Figure 5.1. The processes and information flow, shown in Figure 5.1, use different shapes to describe tasks. In the parallelogram boxes are user inputs, while the processes described in the square-shaped boxes are performed by the RCAT. The RCAT calculates four scores for each crossing selected by the user: safety score, economic score, environmental score, and com- munity livability score. These scores are weighed to reach a final score used to prioritize the crossings under consideration. The RCAT spreadsheet has seven main tabs: download, process, safety module, economic module, environmental module, community module, and final score. In the down- load and process tabs, users select the crossings to be ana- lyzed and download the corresponding data from the FRA website. In the tabs for the safety, economic, environment, and community livability modules, a score for each factor is com- puted. Before the final score is calculated, a relative weight for each factor is selected by the user, with the result of a weighted average score, which is presented in the final score tab. Brief descriptions of the components shown in Figure 5.1 are pre- sented in the following sections. Selection of Crossings The user defines a corridor by selecting crossings along the rail line. The RCAT allows the user to identify grade crossings listed in the FRA database, on the basis of inputs such as state, railroad, and division. The user selects crossings from this refined list, which he/she wishes to consider for prioritization. Download Crossing Information The RCAT is programmed to allow the user to download crossing inventory information from the FRA database directly into the spreadsheet. Information from the FRA inventory database is used in the safety, economic, and community livability module tabs. The RCAT automatically populates the FRA crossing inventory information in these modules using the selection and download steps in the RCATâs download and process tabs. C H A P T E R 5 Overview of the RCAT Development
40 Additional manual inputs are required to populate other data fields, such as accident history at the crossing, fuel costs, and presence of coastal management areas. (These variables are not available in the FRA inventory database.) The RCAT user guide, shown in Appendix C, provides guidance on data sources for these variables. Safety Score A safety score is computed for a crossing on the basis of the accident prediction formula and site-specific adjust- ments applied to individual crossings. The predicted accident frequency is calculated from the modified FRA accident prediction model and site-specific adjustments applied to reflect accident severity. The safety score reflects the effects of variables included in accident prediction and adjustments due to accident history, as well as site-related factors such as crossing angle, maximum timetable train speed, type of crossing surface, and selection of traffic control devices. The safety module tab of the RCAT is programmed to compute this safety score for each crossing. Economic Score The economic score is based on quantitative factors that are monetized, as well as safety savings and other qualitative economic factors. The RCAT calculates an economic score for each crossing selected by the user, such as economic loss, delay/time cost for commuters, and commercial vehicle drivers. The economic module tab of the RCAT is programmed to compute an economic score for each crossing. Environmental Score The environmental score for a crossing is based on presence or absence of environmental variables near the crossings, such as coastal management region, military installations, etc. The environmental module tab of the RCAT computes the environmental score for each crossing under consideration. Community Livability Score The community livability score for a crossing incorporates quantitative risk factors, such as number of hazardous cargo cars, residential population densities, fixed populations, transient populations, emergency service locations and routes, and local agency priorities. The community livability module tab of the RCAT computes the community livability score for each crossing under consideration. Applying Weights to Modules The RCAT also allows users the flexibility to change the relative importance of each module before arriving at a final score. The ability to change the weight (i.e., importance) applied to each module allows a user to apply the tool and address any unique requirements that a region may have. The weights applied to each module can be edited in the final scores tab of the spreadsheet tool. Final Score The final score for each crossing is calculated by using the combined score of the safety, economic, environmental score, Start Select RR Xings to be considered for prioritization Download/Input Xing Information Compute Score for Safety Factors Compute Score for Environmental Factors Compute Score for Economic Factors Select relative weights for each factor Compute Score for Community Livability Factors Fo r e ac h Xi ng c on si de re d Compute Final Score Return Sorted List of Xings End Figure 5-1. Information flow and steps involved in producing output from the RCAT.
41 and community livability module tab scores. This final score is computed in the final scores tab of the RCAT and is used to prioritize the crossings for safety improvements. 5.2 Output of the Methodology and the RCAT The tool returns a weighted score for each of the four mod- ules and calculates a final score. The tool also gives a visu- alization of the weighted scores for each module for each crossing under consideration. A higher score for a crossing implies a higher impact of a grade separation project at that specific location. This system allows a user to see easily the relative impact that a grade separation project can bring about for the cor- ridor. This information is useful for a planner to help make decisions on the selection of a grade separation project along a corridor. The RCAT can be used with relative ease by a practitioner to prioritize crossings along any defined corridor. Indepen- dent analysis of railroad crossings over multiple corridors can also be carried out by using the RCAT.
