Alcohol, Drugs, and Personal Safety
Alcohol
For CDL drivers, 0.04% BAC is a violation; refusal to test is treated like a violation. A first offense can mean loss of CDL. Alcohol affects judgment, vision, and reaction time before you feel drunk.
Drugs
Illegal drugs, misuse of prescription drugs, and some over-the-counter medicines are prohibited. Read labels; ask a pharmacist. Random, pre-employment, post-accident, and reasonable-suspicion tests apply.
Personal safety
Park in well-lit areas, lock doors, don't pick up hitchhikers, and report suspicious activity. If threatened, drive to a safe place and call police.
Worked example
A CDL driver tests 0.03% BAC. Reasoning: under 0.04% is not a per se CDL violation, but it can still support an impaired-driving charge or company action; the safe rule is no alcohol before driving.
Traps
Thinking 0.08% is the CDL limit; refusing a test; assuming prescription drugs are always allowed; leaving the cab unlocked.