When the use of part-time drivers was first proposed, there was some question as to whether they would be as reliable and committed as were full-time drivers. This paper provides comparative data to answer that question. ABSENTEEISM: the data indicate that part-time work has inherently lower absenteeism; holding sick-pay and probation effects constant, part-time drivers have less absenteeism than full-time drivers. This result becomes apparent when following an identical cohort over time as it moves between full-time and part-time work, and also in cross-section data across groups. The data also indicate that increases in the number of sick days allowed cause an increase in absenteeism for both part-time and full-time drivers. ACCIDENTS: holding constant hours of driving exposure, years of experience, and the daily time pattern of accidents, part-time drivers have lower accident rates. However, only one transit agency had sufficient data to permit this standardization. There is also an important daily pattern to accident rates: they do not increase and decrease as a function of the daily traffic cycle, but rather as a function of the daily human cycle--increasing in mid-afternoon to reach approximately the same rate on both weekdays and weekends. ATTRITION: there is a tendency for transit agencies to hire the wrong people for part-time work; 75 to 85 percent of those hired actually wanted full-time work, which leads to greater turnover and increased training costs. The quit rates of part-time drivers vary strongly with external economic conditions, moving inversely with the local unemployment rate.

When the use of part-time (PT) vehicle operators was first proposed, one of the principal concerns was whether part-time operators (PTOs) would be as committed and reliable as were full-time operators (FTOs)• A number of these concerns are examined and it is concluded that, in general, PTOs are dedicated, competent employees whose performance is usually as good as, or better than, that of FTOs. These conclusions are basen nn netAilen r. ARP. studies at five transit agencies. The agencies are a diverse group having a wide variety of experience with PT labor. They range in size from 60 to 1,100 buses, in peak/base ratio from 1.2 to 3.5, and in operating environment from new western suburb to long-established northeastern city. Interviews were conducted from 1982 tu 1984, aml t! ach agency was visited at least twice. Detailed data were collected on scheduling and oper ator pe r formance, and interviews were held with operations managers, department heads, union leaders, and vehicle operators.(De-tailed descriptions of the agencies and methodology are contained in Chomitz and Lave (.~) and Chomitz, Giuliano, and Lave (1_).