The capacity of a bus lane, where buses must follow each other, is well established. There was relatively little information, however, on the bus flow capacity of an arterial that has an exclusive bus lane where buses have partial or exclusive use (i.e., dual bus lanes) of the adjacent lane(s). The level of service (LOS) of these bus facilities and their impact on arterial flow is not addressed in the current edition of the Highway Capacity Manual (HCM). Currently, bus impacts are addressed independently in Chapter 9, Signalized Intersections, and Chapter 12, Transit Capacity, and not at all in Chapter 11, Urban and Suburban Arterials. A comprehensive and consistent procedure for assessing bus flow capacity and LOS, and the impacts of bus flow on arterials was needed.

The objective of this research was to develop a procedure(s) for determining the capacity and LOS of bus flow on arterials with at least one exclusive lane for buses. Situations addressed included those in which buses have one exclusive lane and no, partial, or exclusive (i.e., dual bus lanes) use of adjacent lanes. This research effort did not include assessing the capacity and LOS of the arterial, but did include the impacts of bus flow on the adjacent lane. The procedures developed provide information that can be used to update the HCM primarily Chapters 11 and 12, and possibly Chapter 9.

Status: The revised final report has been published as TCRP Report 26, "Operational Analysis of Bus Lanes on Arterials." TCRP Project A-15 is preparing materials for the Year 2000 edition of the HCM, which includes the results of the research. TCRP Project A-7A is further validating the procedures using additional field data.

TCRP Report 26 is also available in portable document format (PDF). (A free copy of Adobe Acrobat Reader is available at https://www.adobe.com.) Double-click on the links below to access the report.

Front Matter; Chapter 1: Overview of Project and Procedures; Chapter 2: Bus Lane Capacities; Chapter 3: Bus Travel Speeds and Service Levels (2,247 KB)

Chapter 4: Examples of Research Applications; Chapter 5: Interpretation, Appraisal, and Implications; Appendix A: Literature Review; Appendix B: Dwell Range Window Approach to Estimate Speed; References (642 Kb)