Most can’t pass a drug test. I have 70% failure on drug tests - even when you tell them there will be a test. Had one last week show up and blow a 0.14 at he clinic.
I talk to several long haul trucking companies. There is a truck driver shortage in the US. The biggest issue for them is hiring someone who can pass a drug test. As you can guess, the last thing you want to do from a liability standpoint is put a pot head behind the wheel of a $150K semi tractor pulling a $75K trailer that weighs 110,000 pounds.