Will future breathalyzers be able to detect drugs? There are companies working on that as we speak. There are many problems with breath tests for drugs, including the lack of a legal limit for marijuana or many other drugs. Unlike alcohol, where there is a .08% alcohol limit above which one is driving under the influence (DUI), our new article, written by DUI Lawyer Robert Miller, examines the problems and new technologies being tested by several Universities towards developing easy to use breath tests for drugs. Are there breathalyzers that can detect drugs?