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SECTION V--DESCRIPTION OF STRATEGIES Types of Strategies The strategies in this guide were identified from a number of sources, including recent literature, contact with state and local agencies throughout the United States, and federal programs. Some of the strategies are widely used, while a few have been subjected to only a limited number of trial applications to date. 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 thoroughly 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 letter symbol throughout the guide: Proven (P)--Those strategies that have been used in one or more locations and for which properly designed evaluations have been conducted which show them to be effective. These strategies may be employed with a good degree of confidence, but with the under- standing that any application can lead to results that vary significantly from those found in previous experience. The attributes of the strategies that are provided will help the users make judgments about which may be 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 consid- ered. Implementation can proceed with some degree of assurance that there is not likely to be a negative impact on safety, and very likely to be a positive one. It is intended that as implementation of these strategies continues under the AASHTO Strategic Highway Safety Plan initiative, appropriate evaluations will be conducted. As more reliable effectiveness information is accumulated to provide better estimating power for the user, any given strategy labeled "tried" can be upgraded to a "proven" one. Experimental (E)--Those strategies representing ideas that have been suggested, with at least one agency considering them sufficiently promising to try them as an experiment in at least one location. These strategies should be considered only after the others have been determined not to be appropriate or feasible. Even where they are considered, their implementation should initially occur using a controlled and limited pilot study that includes a properly designed evaluation component. Only after careful testing and eval- uations 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 attri- butes of this type of strategy, so that it can be upgraded to a "proven" one or be identi- fied as being ineffective and not worthy of further consideration. V-4