Ms. Arlene S. Doern
Personnel and Risk Manager
C-TRAN
P.O. Box 2529
Vancouver, WA 98668-2529

Dear Ms. Doern:

Please excuse our delay in responding to your letter concerning the application of the Federal Transit Administration's (FTA) drug and alcohol rules to the program conducted by C-TRAN. You state that the number of safety-sensitive employees working for C-TRAN fluctuates daily because of terminations and new hires. You ask how to calculate the size of the random testing pools so as to attain the random testing rates required by FTA's rules.

The drug and alcohol rules set minimum annual random testing rates: 50 percent under the drug rule and 25 percent under the alcohol rule. 49 CFR 653.47(b)(2) and 654.35(a). Both rules require that the dates for administering random tests be "spread reasonably throughout the calendar year." 49 CFR 653.47(b)(2) and 654.35(g). To reasonably spread random tests throughout the year, employers generally select covered employees for random testing on a weekly, bi-monthly, monthly, or quarterly basis; all of these practices are proper under the rules. The size of your pool is determined at the time of your random selection. For instance, if you select quarterly, then you calculate the number of safety-sensitive employees in your random testing pool four times a year. At the end of the calendar year, you determine whether you have met the random testing rate by averaging the four numbers and calculating whether you have tested at least 50 percent of that number of covered employees for drugs and 25 percent for alcohol. I have enclosed a copy of FTA's "Random Drug Testing Manual," which explains in more detail how to conduct random testing.

If you have further questions, please contact Nancy Zaczek of my staff at (202) 366-4011.

Very truly yours,
(Signed)
Patrick W. Reilly
Chief Counsel

Enclosure