The authors examined driving-under-the-influence and implied-consent laws as well as the proposed legislation that appears in the current Uniform Vehicle Code (UVC). Examination of state legislation revealed several statutory barriers to the effective prosecution of the drug-impaired driver. First, the definition of "drug" in many states' statutes is not broad enough to cover the entire range of drugs that can impair driving ability. Second, while the statutes of all states prohibit both alcohol- and drug-impaired driving, most do not expressly prohibit operating a vehicle while under the combined influence of alcohol and other drugs. Third, most implied-consent laws do not authorize analyzing body fluid specimens for drug concentration. Fourth, a drug analysis can be prevented by provisions that limit police officers to taking only certain types of specimens, or that permit a driver to choose certain tests, other than blood, which is the preferred body fluid for drug analysis. Finally, language in many implied-consent statutes that refers to "a test" rather than "tests" could be construed to prevent police officers from demanding a second analysis in case an initial test shows little or no alcohol.