Use of accumulated sick leave for personal reasons. Driver on sick leave need not pay for substitute. Determining pay for substitute drivers. PART 4 RANDOM DRUG TESTING FOR SCHOOL BUS DRIVERS 20-2-1120. 20-2-1121. 91 Definition. School bus drivers subject to random drug and alcohol testing; procedures; costs; rules and regulations. Penalties for violation or refusal to submit to test. Sec. PART 5 SCHOOL BUSES Sec. 20-2-1125.