Can you be charged with a DUI when all that's in your body is caffeine? That's what the courts in California are trying to figure out.

Joseph Schwab was pulled over after driving erratically in Solano County, California. He was administered a breathalyzer test which showed 0.00% blood alcohol level. He was booked into county jail where other toxicology tests were run for cocaine, opiates, THC, methamphetamines and more. The sample was tested by a secondary lab. Both labs showed only the existence of caffeine.

California code defines "drug" to be any substance that could "impair, to appreciable degree" the ability to drive normally. Can caffeine have that effect? Like, "Sir, you're 3 espressos over the legal limit". Not according to Jeffery Zehnder, a forensic toxicologist. Calling the matter "really stupid," Zehnder says he's never seen a court prosecute anyone for caffeine.

Maybe an overzealous police officer or district attorney?

From the account of the officer, it still sound like Schwab may have been driving like a jerk. Which could be a crime if he was indeed driving recklessly and/or putting others in danger. However, that is not a DUI, at least not with what substances we normally take into consideration. Otherwise, I know a lot of drivers would be guilty of driving under the influence of sodas, Starbucks and Dunkin' Donuts.