Intended as a guide to good practices, this report, which updates the 1967 document and expands its coverage, provides discussion, comments and recommendations of AASHTO on several aspects of highway design and practices in relation to safety on road and streets under the control of state and local highway and transportation departments. The application is discussed of safety criteria (program control, low speed and low volume roads, urban and rural conditions, the highway environment, widening right of way, and state of the art) and various design features are considered. Aspects of interchanges and roadside design are covered, as well as roadside appurtenances and traffic operations. Construction and maintenance operations are reviewed, and the programming of safety improvements on existing highways is discussed. Notes on narrow bridges on two-lane highways (an example of discontinuity in the highway environment) are included in an appendix.
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