An ltl truking company, specializing in less-than-truckload shipments, operates a number of terminals that are strategically located across the us. when the loads arrive at a terminal,they are sorted either for delivery to local customers or for transfer to other terminals. The terminal docks are staffed by bid and casual workers. Bid workers are union employees who are guaranteed a 40-hour workweek. A bid employee assigned to one of the standard three shifts of the day of the week. Casual employees are hired temporarily for any number of hours to account for peak loads that may exceed the work capacity of available bid workers. Union contract restricts casual employees to less than 40 hours per week.