The district attorney's office claims the DUI charge is not based upon the evidence of caffeine in his system, but prosecutors have not yet dismissed the charges.

California authorities are reportedly moving forward with a DUI prosecution for a driver that showed only the presence of caffeine in his blood.

The driver, Joseph Schwab, was allegedly driving home from work when a California Department of Alcoholic Beverage Control pulled him over and accused him of driving erratically and cutting her off, according to a Guardian report. The incident led to a misdemeanor charge of driving under the influence of a drug.

Once in police custody, Schwab's breathalyzer test allegedly indicated a 0.00-percent blood alcohol level. A blood test is said to have found no indication of benzodiazepines, cocaine, opiates, THC, carisoprodol, methamphetamine, MDMA, oxycodone or zolpidem. Another review of the blood test by a separate laboratory reportedly showed only the presence of caffeine.

The Guardian report and Schwab's defense attorney imply that he is being prosecuted for being under the influence of caffeine, however the Solano County chief deputy district attorney claims "the charge of driving under the influence is not based upon the presence of caffeine in his system."

Authorities do not necessarily require a positive toxicology test result to pursue drugged-driving charges, instead relying on officer observations as evidence of impairment. A long list of psychoactive compounds and chemical analogues ('designer' drugs) are not included in standard blood tests, including many over-the-counter drugs that can affect the mind in large doses.

Schwab's defense lawyer is attempting to have the case dismissed on the grounds that the charges were not brought until nearly 10 months after he was pulled over.