Truck driving is an interesting case because there are laws restricting when and how long a driver is allowed to operate, and those hours must be logged. At the same time, that logging is done on a company-owned device (or, less and less often now, a paper log booklet), and only when the employee is using the work vehicle.

It's completely unreasonable to expect employees to consent to location tracking when they aren't at work. But if the employer is requiring use of a smartphone app as condition of employment, they need to provide and pay for the device and service, period.