For FMCSA-regulated employers, 49 CFR § 382.305(b) sets the minimum annual random testing rates at 50% of average driver positions for controlled substances and 10% for alcohol.
49 CFR § 382.305(b) — Random testing
(b)(1) Except as provided in paragraphs (c) through (e) of this section, the minimum annual percentage rate for random alcohol testing shall be 10 percent of the average number of driver positions. (2) Except as provided in paragraphs (f) through (h) of this section, the minimum annual percentage rate for random controlled substances testing shall be 50 percent of the average number of driver positions.
The rates in § 382.305(b) are floors, not targets, and the regulation gives the FMCSA Administrator authority to raise or lower them based on the industry-wide violation rate reported through the drug and alcohol management information system. FMCSA announces the applicable rate in the Federal Register. Check the current year's notice before setting your pool percentage — and note that other DOT agencies (FAA, FRA, FTA, PHMSA, USCG) set their own rates independently.
The calculation is based on the average number of driver positions across the year, not a headcount on one day. Seasonal operations and carriers with turnover routinely get this wrong by computing against a peak or a trough.
A common compliance failure is running all required tests in December to hit the number. Random means unannounced and unpredictable; selections should be reasonably distributed across the year, and every covered driver must be in the pool for every selection.
We run the selections, track the rate, and keep your documentation audit-ready.
Learn more →For FMCSA-regulated employers the rate codified at 49 CFR § 382.305(b)(2) is 50% of average driver positions for controlled substances. The 25% figure people remember is a historical rate and a rate used by some other DOT agencies; it is not the current FMCSA minimum.
The rate is applied to the average number of driver positions over the year, so a pool that changes size is handled by the averaging rather than by recalculating from a single point in time.
Yes. Section 382.305(j)(2) permits an employer to use a service agent such as a C/TPA, and your drivers may be part of a larger pool — but you must ensure the service agent tests at the rate for your industry and that only covered employees are in the pool.
Regulatory text on this page was verified against the current eCFR on August 31, 2026. This is general compliance information, not legal advice. Questions? Call (888) 869-0898.