What GAO Found

Federal regulations require employers in the different transportation industries to: (1) randomly test their safety-sensitive employees for drugs or alcohol, or both, and (2) certify and report the aggregate data annually or when requested to the Department of Transportation (DOT). The DOT modal administrations and the U.S. Coast Guard (USCG) primarily use these data to determine the annual random testing rate (the specified minimum percentage of these employees that employers use to calculate the minimum number of random tests they must conduct that year). For example, for drugs, if 1 percent or more of employees in an industry randomly test positive, then the following year's random testing rate will be set at 50 percent.

DOT, the modal administrations, and USCG have taken steps to ensure that drug and alcohol testing data reported by employers are reliable:

• DOT incorporated automated checks to alert employers that the data they are submitting are outside of expected ranges and may be inaccurate.

• After data are reported, the modal administrations and USCG use varying processes to verify data, e.g., some compare data employers reported to physical records during routine compliance reviews.

These data verification processes improve the reliability of the data, but are not consistently used by each of the modal administrations and USCG. Officials have the discretion to use different data reliability processes and may have valid reasons for doing so. However, officials have not evaluated the sufficiency of these various processes and therefore do not have adequate assurance the data are reliable for calculating the random testing rates.

Laboratory Urinalysis for Drug Testing

In March 2019, DOT published aggregated drug and alcohol testing data on its website, as required. This website, updated annually, follows several key actions for transparently reporting government data, but does not follow other key actions, including:

• DOT has not disclosed known data limitations that exist in the public data that would prevent users from accurately calculating the random testing rate.

• DOT has not engaged with the public to encourage data use.

DOT officials told us there is limited interest in the data based on website traffic. However, because DOT has not taken steps to inform the public of the data, DOT may be missing opportunities to identify additional users and improvements.

Why GAO Did This Study

Since 1988, DOT has regulated the process by which employers in the different transportation industries (aviation, trucking, rail, transit, pipeline, and maritime) are required to test their employees for drug and alcohol use. Employers must self-report these test results annually to DOT or when requested by DOT. In a 2018 statute, Congress required DOT to publish the aggregate drug and alcohol testing data on DOT's website and included a provision for GAO to review the website and these data.

This report examines: (1) how DOT uses drug and alcohol testing data, (2) how DOT verifies that data are reliable, and (3) whether DOT follows key actions for transparently reporting drug and alcohol testing data. GAO reviewed relevant laws and regulations, among other things. To determine how DOT verifies that data are reliable, GAO reviewed documents, analyzed data in the internal database from calendar years 2003 through 2018, and interviewed DOT officials. GAO also reviewed the public website and compared it to key actions for open government data.