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The 1965 Highway Capacity Manual became an essential tool in planning, designing, operating, and managing roadway facilities. The production and distribution of thirty thousand copies of the document indicated its extensive use and acceptance. Yet, since 1965, emphasis shifted from new facility construction to the upgrading of existing facilities and the implementation of operational techniques. Factors such as the presence of pedestrians, bicycles, and bus transit along roadways and the needs for environmental and user cost analyses became important in engineering and planning. Considerable research on these and other topics was undertaken following publication of the 1965 Manual. This Circular was produced to addresses the need - identified by a survey of Highway Capacity Manual users - for a compilation of then-current procedures to supplement the Manual.