Keep in mind when booking a motorcoach trip, do not compromise safety to save a dollar. 
All us motorcarriers are subject to legal hours of service regulations. Those differ between cargo carriers and passenger carriers and you should be aware of the passenger carrier regulations when booking a trip. 

The regulations for passenger carriers are:

§395.5 Maximum driving time for passenger-carrying vehicles. 
Subject to the exceptions and exemptions in §395.1:
(a) No motor carrier shall permit or require any driver used by it to drive a passenger-carrying commercial motor vehicle, nor shall any such driver drive a passenger-carrying commercial motor vehicle:
(a)(1) More than 10 hours following 8 consecutive hours off duty; or
(a)(2) For any period after having been on duty 15 hours following 8 consecutive hours off duty.
(b) No motor carrier shall permit or require a driver of a passenger-carrying commercial motor vehicle to drive, nor shall any driver drive a passenger-carrying commercial motor vehicle, regardless of the number of motor carriers using the driver’s services, for any period after-
(b)(1) Having been on duty 60 hours in any 7 consecutive days if the employing motor carrier does not operate commercial motor vehicles every day of the week; or
(b)(2) Having been on duty 70 hours in any period of 8 consecutive days if the employing motor carrier operates commercial motor vehicles every day of the week.
[68 FR 22516, April 28, 2003; 70 FR 50071, Aug. 25, 2005]

The basic rule of thumb is: If traveling more than 600 miles your driver will exceed their legal hours of service. To prevent this, we will arrange for a driver switch. Driver switches do add to the price of the overall trip by about 20% but also make the trip safe.