The determination of whether show-up, stand-by, on-call or reporting time are compensable is dependent on a number of variables. Employees may be "engaged to wait" or they may be "waiting to be engaged". “If an employee reports for duty and is required to wait before being assigned work or told that no work is available, the waiting time is compensable. In such instances, the employee is "engaged to wait" (29 C.F.R. § 785.14). If the employee reports for duty and is required to wait before work is completed on a vehicle, then that employee is "waiting to be engaged". 29 C.F.R. § 785.15 and 29 C.F.R. § 785.16(b). In either event, the employee is unable to use the time effectively for his/her own purposes. It belongs to and is controlled by the employer.