Actually, they cannot force you to use your 16 rule. That's drivers discretion.
Everything else is spot on.
Policy says the driver is responsible to communicate the situation to his supervisor allowing a discussion of what works best to form a decision (use your 16 or get picked up). "Driver discretion" focuses on Saturday's and closed terminals. If no one is available at the service center then the driver is expected to use his discretion in using the exemption.