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4 of trucks (fewer than 250 trucks per hour) and 12 ft wide for Eligibility requirements (who may use the shoulder); highways with high truck volumes. Shoulder cross slopes for Benefits and impacts (travel time savings, reliability im- drainage purposes are typically 2% to 6%. Some shoulders provements, affordability, ease of implementation, etc.); also have storm drain catch basins and electrical junction Driver and passenger attitudes; boxes located within their right-of-way. The cost and right- Costs (construction, maintenance, bus operations, etc.); of-way implications on adjacent lane widths may therefore and become a problem in converting the shoulder facilities to Use of emerging technologies. accommodate heavy buses. A review of the relevant literature was combined with sur- Safety is always an important issue. In addition to concerns veys of selected transit agencies and roadway jurisdictions to raised about compromising the intended functions for freeway define the current state of the practice. Based on the survey shoulders, concerns exist regarding increased accident risk. results, in-depth case studies were developed to profile inno- Most motorists do not expect traffic in the shoulder "lane" and vative and successful practices, as well as lessons learned, therefore the potential for accidents increases for basic on- and including where and why implementation did not occur. off-ramp traffic maneuvers as well as for motorists moving Gaps in the desired information were substantial. onto the shoulder when their vehicle becomes disabled. A number of communities allow general traffic to use DEFINITIONS AND ACRONYMS shoulder lanes during peak commute times. This TCRP BBS (bus bypass shoulder)--used in this report to describe synthesis report focuses only on shoulder use applications bus use of highway shoulder lanes to bypass congestion. restricted to buses. It does not include shoulders used for general traffic or on-ramp bypasses. MUTCD--Manual of Uniform Traffic Control Devices for SCOPE Streets and Highways (2), published by FHWA. Station stopping--a mode of bus operations on freeways The two purposes of this synthesis are to: where buses on a route make stops at all or most inter- changes along the corridor. 1. Identify and obtain information and experiences about Queue jumper--physical facility that allows eligible traffic jurisdictions that allow bus use of shoulders, and to bypass localized congestion. 2. Identify and obtain information about which jurisdic- HOV (high-occupancy vehicle)--generally defined as ei- tions have considered but have not implemented these ther two or more or three or more persons per vehicle. treatments and the reasons why. Direct HOV access ramps--most HOV lanes are located in the median of freeways and require carpoolers and buses The transit and highway perspectives on bus shoulder op- to weave across general traffic lanes to enter and exit the erations are reviewed, recognizing that both must be partners freeway using ramps located on the right side of the free- in expanding promising applications for increasing patron- ways. Direct access ramps eliminate the weaving for age and improving operating efficiency. The following types buses and HOVs by providing entry and exit access of information were sought: ramps directly to the center median HOV lanes. These direct ramps are costly, need additional rights-of-way, Institutional setting; and add to the visual impact of freeway interchanges. Planning, design, and implementation process; Legal aspects (liability, legal requirements, and vehicle codes, etc.); REPORT ORGANIZATION Operating guidelines (operating speeds, hours of use, driver operating instructions, etc.); Following the introductory chapter, the synthesis provides an Design standards and/or required physical improve- overview of findings (chapter two), which is followed by ments, including traffic markings and signage, lane case studies (chapter three) and the conclusions and sug- widths, pavement depths, drainage, etc.; gested areas for further research (chapter four). Case study Maintenance and roadway performance; descriptions were prepared for the MinneapolisSt. Paul Enforcement and violation experience; Twin Cities Area; Falls Church, Virginia; Miami, Florida; Bus and passenger volumes; San Diego, California; Toronto, Canada; and Dublin, Impact on highway operations; Ireland. Survey questionnaire tools and respondents are iden- Safety experience; tified in the appendixes.