They are - there's an 8-hour rule and a 12-hour rule but I don't know the specifics. In the end, it doesn't matter. If the delivery/route is 360 miles round-trip (using easy numbers for the math), at 60 mph, it will take 6+ hours driving time. Have to pad that 6 hours with slower speeds unless your origin and destination are right next to the highway. Add in time for loading or unloading. Add in time to eat. I suspect if you did this in 7-8 hours, your boss will be happy. If you take 9-10 hours - 'cause you're paid by the hour - that won't fly for long.