When someone’s been arrested for a DUI after doing their field sobriety tests and possibly a preliminary alcohol screening breath test, they’re supposed to be consulted about their choice of tests. If the officer believes they’re under the influence of drugs, they usually will not give them a choice of tests and instead tell them that they have to do a blood test.
Individuals should avoid a drug test if they have taken any drugs when deciding to perform a breath or blood test. That will give the arresting officer more evidence of potential impairment