(a) Except as provided in subsection (b) of this section, an employer is not subject to liability under this subchapter, on account of the failure of the employer to pay an employee minimum wages or to pay an employee overtime compensation, for or on account of any of the following activities of the employee:

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

(2)

(A) An activity that is preliminary to or postliminary to the principal activity or activities, which occurs either before the time on any particular workday at which the employee commences or subsequent to the time on any particular workday at which he or she ceases the principal activity or activities.

(B) For purposes of subdivision (a)(2)(A) of this section, the use of an employer's vehicle for travel by an employee and activities performed by an employee that are incidental to the use of the vehicle for commuting shall not be considered part of the employee's principal activities if the use of the 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 the employee.

(b) Notwithstanding the provisions of subsection (a) of this section that relieve an employer from liability and punishment with respect to any activity, the employer is not relieved from liability if the activity is compensable by either:

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

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

(c) For the purposes of subsection (b) of this section, an activity shall be considered as compensable under a contract provision or a custom or practice only when the activity is engaged in during the portion of the day with respect to which it is compensable.

(d) In the application of the minimum wage and overtime compensation provisions of this subchapter, in determining the time for which an employer employs an employee with respect to walking, riding, traveling, or other preliminary or postliminary activities described in subsection (a) of this section, the time, but only that time, during which the employee engages in any activity which is compensable within the meaning of subsections (b) and (c) of this section shall be counted.

(e) This section applies only to conduct occurring on or after April 5, 2017.