Drivers are drawn at random by the drug consortium for testing each calendar quarter.  The consortium notifies our office with the names of the drivers and the timeframe they have to report.....drivers have no prior warning of the schedule.  They are made aware at hire that compliance with the consortium is a condition of employment.  This, and working with a good insurance company who does thourough background checks has helped us avoid a lot of issues that other companies may have had to face.