first - Short haul trucking
first - Short haul trucking (less than 150 mi radius) accounts for about 1/3 of all truck drivers, over 200,000 jobs. So not exactly a small number.
second - long haul drivers are legally required to stop and rest every 8 hours of driving, and can't drive more than 11 hours per day. so an 1800 mile (~30 hour) trip would require stops, even with two drivers.