DOT Drug Testing Rate Calculator

The minimum annual rates are 50% for controlled substances and 10% for alcohol, applied to the average number of driver positions. This turns that into a number of selections and a quarterly plan you can hand to a consortium.

Selections owed this year

Enter the average number of driver positions across the year — not the headcount today. Fractions round up, because you cannot test 4.5 drivers.

Controlled substances, 50%
5
Alcohol, 10%
1
Drug selections still owed
5
QuarterQ1Q2Q3Q4
Drugs2111
Alcohol1000

Selections must be spread reasonably through the year. Running the whole year's count in one quarter meets the number and fails the requirement.

Low-poly render of a specimen cup on a clinic counter
A programme measured in selections, not in intentions.

What it checks

Two percentages against one number, rounded up, then divided across four quarters as evenly as whole selections allow. The quarterly row matters more than the annual total: an auditor reading a year of selections that all happened in one month has found a programme that was reconstructed, not run.

Worked example

A carrier averages ten driver positions. At 50% that is 5 controlled-substance selections and at 10% it is 1 alcohol selections — spread as roughly one or two a quarter each, not five in December.

The same driver can be selected twice in a year. Random means random; removing a name because it came up last quarter is exactly what makes a selection non-random and is a finding in its own right.

The rule it comes from

49 CFR §382.305(b) — the minimum annual percentage rate for random alcohol testing is 10% of the average number of driver positions, and for random controlled substances testing 50%. Paragraphs (c) to (h) let the Administrator raise or lower those rates on the industry violation rate, effective 1 January after publication.

Because the rate can move, check the current figure before you plan a year. The link below is the section itself, which is the only version that is ever current.

Sources

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