Hart said these issues are a reminder that there is much to be done to eliminate safety risks due to the presence of substance impaired operators in our transportation systems. Eliminating substance impaired driving, reaching zero remains a battle that is far from over. Eradicating impairment by drug use across all modes of transportation is an even loftier goal. An ongoing critical first step is improving the standardization of data, an important effort to improve transportation safety. 

In 1992, the NTSB published a safety study, Alcohol and Other Drug Involvement in Fatal General Aviation Accidents, 1983 through 1988. There were only a small number of fatal general aviation accidents during the study period—35—in which the NTSB cited drugs as a cause or factor.  Multiple drug use was identified in 15 (43 percent) of the 35 accidents. 

Of the drugs detected in toxicological tests, cocaine and marijuana were the most frequently identified (12 and 9 accidents, respectively).  The study noted, however, that due to quality control problems at the laboratory used by the NTSB to test for drugs of abuse, few conclusive toxicological tests for drugs were obtained by the agency and test results from the years of the study period were less reliable than test results from the latter years of the study period.  Since 1990, those issues have been resolved.