This study examines the extent to which part-time operators (PTOs) are currently used by the U.S. transit industry and identifies methods used to assign PTOs to work assignments for existing schedules. Also methods used to consider PTOs in preparation of transit schedules are also examined. PTO utilization can be affected by work rules and other provisions of labor agreements. Chapter 2 describes the extent of PTO use and provides a national perspective on the range and norms of contractural provisions affecting PTOs. PTO wages, work rules and fringe benefits are described. Chapter 3 covers the rationale for selecting the transit agencies contacted; each such agency is then described in terms of operating characteristics and number of PTOs utilized. Incorporating PTOs into runcutting and evaluation of PTO utilization are briefly discussed. Chapter 4 describes methodologies currently used by three transit systems to assign PTOs to segments of work selected from current runcuts. A critique of each method is provided. Chapter 5 describes how three transit agencies have modified existing runcuts in order to make the cost effective use of PTOs. Chapter 6 presents a summary of PTO labor practices, identifying methods which could be considered and recommeded future research.