Why do trucking companies hire the worst drivers?

I'm eastbound on I-70, Denver on Feb. 9, 2011 when a Conway Semi Truck veered into my lane. I brake hard. After a while he returns to the middle lane. I pull along side and he veers into my lane again. This time I nearly crash into the median. Once may be accidental, twice is intentional. I get his truck number and license plate. He returns to the middle lane and I attempt to get by him once more. Yes ~ you guessed it ~ over he swerves again into my lane. The next time he returns to the middle lane I zoom by and he has the audacity to flip off my 14 year old daughter! The next day I call Conway Trucking and report him. I'm told if he gets 2 complaints in 3 months, they will TALK to him. Big deal! And that is why truck drivers are the worst. Absolutely NO consequences until they kill or maim someone.