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SECTION V--DESCRIPTION OF STRATEGIES Classification of Strategies The strategies in this guide were identified from a number of sources, including the literature, contact with state and local agencies throughout the United States, and federal programs. Some of the strategies are widely used, while others are used at a state or even a local level. Some have been subjected to well-designed evaluations to prove their effectiveness. On the other hand, it was found that many strategies, including some that are widely used, have not been adequately evaluated. The implication of the widely varying experience with these strategies, as well as the range of knowledge about their effectiveness, is that the reader should be prepared to exercise caution in many cases, before adopting a particular strategy for implementation. To help the reader, the strategies have been classified into three types, each identified by a letter symbol throughout the guide: Proven (P): Those strategies which have been used in one or more locations and for which properly designed evaluations have been conducted that show them to be effective. These strategies may be employed with a good degree of confidence, but with an understanding that any application can lead to results that vary significantly from those found in previous evaluations. The attributes of the strategies that are provided will help the user judge which strategies are the most appropriate for their particular situation(s). Tried (T): Those strategies that have been implemented in a number of locations and may even be accepted as standards or standard approaches, but for which there have not been found valid evaluations. These strategies, while in frequent, or even general, use, should be applied with caution, carefully considering the attributes cited in the guide, and relating them to the specific conditions for which they are being considered. Implementation can proceed with some degree of assurance that there is not likely to be a negative impact on safety, and there very likely will be a positive one. It is intended that as the experiences of implementation of these strategies continue under the AASHTO Strategic Highway Safety Plan initiative, appropriate evaluations will be conducted, so that effectiveness information can be accumulated to provide better estimating power for the user and so that the strategy can be upgraded to "proven" status. Experimental (E): Those strategies that are ideas that have been suggested and that at least one agency has considered sufficiently promising to try on a small scale in at least one location. These strategies should be considered only after the others have proven not to be appropriate or feasible. Even where they are considered, their implementation should initially occur using a very controlled and limited pilot study that includes a properly designed evaluation component. Only after careful testing and evaluations show the strategy to be effective should broader implementation be considered. It is intended that as the experiences of such pilot tests are accumulated from various state and local agencies, the aggregate experience can be used to further detail the attributes of this type of strategy so that it can be upgraded to "proven" status. It is particularly difficult to evaluate the impacts of countermeasures on bicyclist crashes for the following reasons: Bicycle crashes are substantially more rare than vehicle crashes not involving bicyclists, making it difficult to assess impacts at a given location and over reasonable lengths of time. V-4