Labor productivity in transportation service has declined in recent decades (citation). Unions have grown in membership and influence and have often won workers such contract elements as the eight-hour work day. As an example, the eight-hour work day brings workers stable income and often benefits associated with full-time employment. Transit operation, however, does not lend its self well to eight-hour work shifts. Because transit demand peaks in the morning and afternoon commute times, more workers are needed during these periods than in the middle of the workday. Without part time or flexible shift workers, transit agencies are forced to staff full-time vehicle operators to their highest peak demand, loosing many hours of productivity when these same workers are idle midday. Several strategies exist for increasing labor productivity.