Implementation Guidelines - Federal Transit Administration - U.S. ...

1. Determine how frequently random draws are made (daily, weekly, monthly, quarterly,
etc.). This is the testing period.
2. For each testing period, determine the number of safety-sensitive employees that are in
the pool. Be sure to update the file prior to the random draw to ensure that all new hires
and individuals placed into active status have been added to the pool, and those who have
been discharged or put on inactive status have been removed.
3. Calculate the number of tests to be performed during the testing period as follows:
Testing
Period
a. Multiply the number of safety-sensitive employees in the pool at the beginning of the
testing period by the required testing rate (50 percent for drugs and 10 percent for
alcohol).
b. Divide the total by the number of testing periods in the year (quarterly = 4; monthly =
12; weekly = 52; and daily = 365).
The result is the number of tests to be performed for that testing period. This method is
demonstrated in the table provided below.
Safety-
Sensitive
Employees in
Period (A)
Test
Periods
Per Year
(B)
Random
Rate
Drug
(C)
Random
Rate
Alcohol
(D)
# of Drug
Tests
Required
(A*C)/B
# of
Alcohol
Tests
Required
(A*D)/B
Quarter 1 160 4 50% 10% 20 4
Quarter 2 126 4 50% 10% 16 4
Quarter 3 62 4 50% 10% 8 2
Quarter 4 168 4 50% 10% 21 5
Total Year 65 15
4. Once the number of tests per testing period has been calculated, the total should be
adjusted for cancelled tests.
Figure 6-1. Method for Calculating the Number of Random Tests
Chapter 6. Types of Testing 6-15 August 2002