Ensure that all shipments are NOT HAZARDOUS materials. Do not accept shipments from unknown persons. Do not transport firearms or cash. Have a designated person in the corporate structure who is "The One" who everyone calls for advice on procedures and policies. Have a consistent policy that every one works with, and that is well publicized in the company hand book.
Have a safety manager who has the power to discipline and fire employees who don't work and drive safely. Use a driver observation company to watch and report on new hires to make sure they are good safe drivers. Have a driver trainer to make sure new drivers know that they WILL be under observation at various times of the month, and to teach good driving habits, and safety awareness.