The 1988 AASHTO Roadside Design Guide includes general warrants for the use of traffic barriers and other safety appurtenances. However, these warrants do not address the cost-effectiveness of such installations. The Roadside Design Guide also includes information on a computer program, ROADSIDE, which was developed for cost-effectiveness analysis; however, agencies attempting to use it have experienced difficulties, and some have found the results questionable. Further, current research is focused on the development of performance-level design criteria is to provide safety features that are better tailored to the specific conditions of a site. The current version of ROADSIDE does not readily allow the analysis of different performance levels. Research is needed to develop improved software for cost-effectiveness analysis of roadside features and to formulate procedures for using the software to apply the performance-levels concept.
The objective of this project was to develop improved microcomputer-based cost-effectiveness analysis procedures for use in (1) assessing alternative roadside safety treatments at both point locations and sections of roadway, and (2) developing warrants and guidelines including those which consider performance levels of safety features.
To achieve these objectives the following tasks are envisioned: (1) Identify and assess current procedures, both manual and computerized, for cost-effectiveness analysis related to the selection of roadside safety features. ROADSIDE and the FHWA program BCAP shall be included in the assessment. (2) Conduct a detailed evaluation of the most promising procedures and software. This evaluation shall be performed to assess the strengths and limitations including, at a minimum, range of applicability, ease of use, data requirements, and flexibility. Evaluations shall also include a limited survey of user experience with the procedures and software. (3) Prepare an interim report documenting the efforts completed, and recommending a course of action. The interim report shall include a description of the software and procedures proposed and a detailed work plan describing the activities that will be performed. A meeting of the project panel and researchers will be held to discuss the results and the recommended course of action, and to agree on a plan of work. (4) Develop improved software and procedures for an IBM-compatible microcomputer at a reasonable speed, using a commonly available language that does not require additional end-user hardware or software acquisition. (5) Test, modify, as necessary, and validate the improved software and procedures using existing data bases applied to actual highway locations. (6) Develop procedures for user agencies to establish systemwide warrants for common situations through use of the software. (7) Prepare a user's manual, which describes the capabilities and limitations of the system, and provides instructions for operating, customizing, and updating the system. The user's manual shall also include a variety of examples depicting program inputs and outputs. These examples shall, as a minimum, include a spot location, a highway section, a performance-level-based analysis, and the development of generalized systemwide warrants. (8) Submit a final report documenting the research effort, including application examples, the user's manual, and the software documentation.
: The project has been completed.
The final report is available as NCHRP Report 492
. The user's manual and software (CRP-CD -33) is also available.