Caffeine may be the "nootropic" brain drug of choice in Silicon Valley, but an hour's drive north in Solano County, California, the stimulant could get you charged with driving under the influence.

That is according to defense attorney Stacey Barrett, speaking on behalf of her client, Joseph Schwab.

After being pulled over on 5 August 2015, Schwab was charged by the Solano County district attorney with misdemeanor driving under the influence of a drug.

Almost 18 months later, Schwab is preparing to go to trial. The only evidence the DA has provided of his intoxication is a blood test showing the presence of caffeine.

Shcwab was driving home from work when he was pulled over by an agent from the California department of alcoholic beverage control, who was driving an unmarked vehicle. The agent said Schwab had cut her off and was driving erratically.

The 36-year-old union glazier was given a breathalyzer test which showed a 0.00% blood alcohol level, his attorney said. He was booked into county jail and had his blood drawn, but the resulting toxicology report came back negative for benzodiazepines, cocaine, opiates, THC, carisoprodol (a muscle relaxant), methamphetamine/MDMA, oxycodone, and zolpidem.