Code of Federal Regulations Title 29. Labor § 29.785.50 Section 4 of the Portal-to-Portal Act

(1) Walking, riding, or traveling to and from the actual place of performance of the principal activity or activities which such employee is employed to perform, and

(2) Activities which are preliminary to or postliminary to said principal activity or activities, which occur either prior to the time on any particular workday at which such employee commences, or subsequent to the time on any particular workday which he ceases, such principal activity or activities. For purposes of this subsection, the use of an employer's vehicle for travel by an employee and activities performed by an employee which are incidental to the use of such vehicle for commuting shall not be considered part of the employee's principal activities if the use of such vehicle for travel is within the normal commuting area for the employer's business or establishment and the use of the employer's vehicle is subject to an agreement on the part of the employer and the employee or representative of such employee.

(1) An express provision of a written or nonwritten contract in effect, at the time of such activity, between such employee, his agent, or collective-bargaining representative and his employer;  or

(2) A custom or practice in effect, at the time of such activity, at the establishment or other place where such employee is employed, covering such activity, not inconsistent with a written or nonwritten contract, in effect at the time of such activity, between such employee, his agent, or collective-bargaining representative and his employer.