The U.S. Department of Labor, Wage and Hour Division, makes the following statement on its web site at DOL.GOV:

Work Hours/Travel Time

"Time spent traveling during normal work hours is considered compensable work time. Time spent in home-to-work travel by an employee in an employer-provided vehicle, or in activities performed by an employee that are incidental to the use of the vehicle for commuting, generally is not "hours worked" and, therefore, does not have to be paid. This provision applies only if the travel is within the normal commuting area for the employer's business and the use of the vehicle is subject to an agreement between the employer and the employee or the employee's representative."