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23 TABLE 12 the majority of companies in the national fleet but include WEIGHTED YEARLY DRUG POSITIVITY RATES (%) BY relatively few drivers. NONRANDOM TEST TYPE Test Reason 2003 2004 2005 2006 2007 2008 One minor note of caution about the relatively low Pre-employment 3.10 2.20 2.10 1.90 1.60 1.28 response rates in the surveys is warranted. For the 2008 Postcrash 1.90 2.50 2.40 1.90 2.70 2.04 survey, for example, drug survey forms were sent to 2,973 randomly selected motor carriers, covering 443,340 com- Reasonable 19.40* 40.30 16.70 30.00 48.00 39.37 Suspicion mercial drivers. The survey was completed and returned to FMCSA by 2,266 (76%) of the carriers. Of those, 1,678 Return-to-Duty 3.60 9.30* 2.60 5.40* 6.50* 1.03 provided usable data on random drug tests. Thus, usable Follow-up 3.10 3.80 2.40 1.90 1.60 3.70 data on random drug tests were obtained from 56% of the Phencyclidine 0.00* 0.10* 0.00* 0.00 total company sample. Concerns about the relatively low Note: Estimates marked with an asterisk (*) must be interpreted with caution response rate are mitigated by the sound sampling meth- because of extremely low precision. odology, and there are no reasons to infer systematic dif- ferences between the carriers that provided usable data and carriers that did not. Nonetheless, a higher response rate TABLE 13 would have been preferable. WEIGHTED YEARLY ALCOHOL POSITIVITY RATES (%) BY TEST REASON Test Reason 2003 2004 2005 2006 2007 2008 PIPELINES Pre-employment 0.01* 0.01* 0.03* 1.20* 0.20* 0.01* PHMSA defines a small employer as having 50 or fewer Random 0.20 0.10 0.20* 0.30 0.25 0.19* employees and a large employer as having 51 or more Postcrash 0.10* 0.10* 0.10* 0.30 0.10 0.13 employees. For 2008, the compliance rate in submitting data Reasonable 24.20 11.00 6.40 32.20* 29.40* 11.30 to PHMSA was nearly 100% for large employers and 55% Suspicion for small employers. Because small employers represent a Return-to-Duty 0.00* 0.40* 0.05* 0.10* 0.60* 0.00* relatively small percentage of the total workforce, however, Follow-up 4.70* 0.20* 0.20 0.10* 0.20 2.45* it is estimated that the available data represent 96% of the Note: Estimates marked with an asterisk (*) must be interpreted with caution total safety-sensitive workforce. because of extremely low precision. Tables 14 and 15 report the PHMSA 2008 drug and alco- hol test results, respectively. Figure 5 shows the drug and Based on the 2008 survey results (Khan 2010), 48% of all alcohol positivity rates by test type. motor carriers have alcohol- and drug-testing programs in place, covering 89% of all commercial drivers. The two per- For drugs, random tests had the highest number of posi- centages are explained by the fact that small carriers, which tives, followed by pre-employment and follow-up tests. tend to be less compliant with DOT regulations, constitute Reasonable cause was the type of test with the highest TABLE 14 PHMSA 2008 DRUG TEST RESULTS Refusals Total Number of Test Positive for Cocaine Positive for Opiates Verified Negative Verified Positive Tests for One or Cancelled Tests Amphetamines Other Refusals "Shy Bladder" Phencyclidine Test Reason More Drugs Adulterated Positive for Positive for Positive for Substituted Marijuana Results Tests Pre-employment 18,174 17,949 210 168 24 1 2 18 3 2 0 10 50 Random 38,229 37,985 225 139 61 4 13 10 5 2 4 8 116 Postaccident 637 627 10 7 1 0 2 0 0 0 0 0 0 Reasonable Cause 70 58 12 5 7 0 0 1 0 0 0 0 1 Return-to-Duty 208 203 5 4 1 0 0 0 0 0 0 0 0 Follow-up 2,371 2,349 19 11 6 0 1 1 0 0 0 3 1 Total 59,689 59,171 481 334 100 5 18 30 8 4 4 21 168