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OCR for page 119
SECTION VI--GUIDANCE FOR IMPLEMENTATION OF THE AASHTO STRATEGIC HIGHWAY SAFETY PLAN Implementation Step 6: Evaluate Alternatives and Select a Plan General Description This step is needed to arrive at a logical basis for prioritizing and selecting among the alternative strategies or program packages that have been developed. There are several activities that need to be performed. One proposed list is shown in Appendix P. The process involves making estimates for each of the established performance measures for the program and comparing them, both individually and in total. To do this in a quantitative manner requires some basis for estimating the effectiveness of each strategy. Where solid evidence has been found on effectiveness, it has been presented for each strategy in the guide. In some cases, agencies have a set of crash reduction factors that are used to arrive at effectiveness estimates. Where a high degree of uncertainty exists, it is wise to use sensitivity analyses to test the validity of any conclusions that may be made regarding which is the best strategy or set of strategies to use. Further discussion of this may be found in Appendix O. Cost-benefit and cost-effectiveness analyses are usually used to help identify inefficient or inappropriate strategies, as well as to establish priorities. For further definition of the two terms, see Appendix Q. For a comparison of the two techniques, see Appendix S. Aspects of feasibility, other than economic, must also be considered at this point. An excellent set of references is provided within online benefit-cost guides: One is under development at the following site, maintained by the American Society of Civil Engineers: The other is Guide to Benefit-Cost Analysis in Transport Canada, September 1994, An overall summary of this document is given in Appendix V. In some cases, a strategy or program may look promising, but no evidence may be available as to its likely effectiveness. This would be especially true for innovative methods or use of emerging technologies. In such cases, it may be advisable to plan a pilot study to arrive at a minimum level of confidence in its effectiveness, before large-scale investment is made or a large segment of the public is involved in something untested. It is at this stage of detailed analysis that the crash reduction goals, set in Step 3, may be revisited, with the possibility of modification. It is important that this step be conducted with the full participation of the stakeholders. If the previous steps were followed, the working group will have the appropriate representation. Technical assistance from more than one discipline may be necessary to go through more complex issues. Group consensus will be important on areas such as estimates of effectiveness, as well as the rating and ranking of alternatives. Techniques are available to assist in arriving at consensus. For example, see the following Web site for an overview: VI-15

OCR for page 119
SECTION VI--GUIDANCE FOR IMPLEMENTATION OF THE AASHTO STRATEGIC HIGHWAY SAFETY PLAN Specific Elements 1. Assess feasibility 1.1. Human resources 1.2. Special constraints 1.3. Legislative requirements 1.4. Other 1.5. This is often done in a qualitative way, to narrow the list of choices to be studied in more detail (see, for example, Appendix BB) 2. Estimate values for each of the performance measures for each strategy and plan 2.1. Estimate costs and impacts 2.1.1. Consider guidelines provided in the detailed description of strategies in this material 2.1.2. Adjust as necessary to reflect local knowledge or practice 2.1.3. Where a plan or program is being considered that includes more than one strategy, combine individual estimates 2.2. Prepare results for cost-benefit and/or cost-effectiveness analyses 2.3. Summarize the estimates in both disaggregate (by individual strategy) and aggregate (total for the program) form 3. Conduct a cost-benefit and/or cost-effectiveness analysis to identify inefficient, as well as dominant, strategies and programs and to establish a priority for the alternatives 3.1. Test for dominance (both lower cost and higher effectiveness than others) 3.2. Estimate relative cost-benefit and/or cost-effectiveness 3.3. Test productivity 4. Develop a report that documents the effort, summarizing the alternatives considered and presenting a preferred program, as devised by the working group (for suggestions on a report of a benefit-cost analysis, see Appendix U). 4.1. Designed for high-level decision makers, as well as technical personnel who would be involved in the implementation 4.2. Extensive use of graphics and layout techniques to facilitate understanding and capture interest 4.3. Recommendations regarding meeting or altering the crash reduction goals established in Step 3. VI-16