New court documents say John Giumarra III had a blood alcohol level of 0.18, twice the legal limit in California.
Giumarra said he believed he collided with something in the roadway.
An officer on scene said Giumarra had an odor of alcohol coming from his breath which prompted a breathalyzer test.
Giumarra was on DUI probation stemming from a 2015 case.
Giumarra will be in court next month for allegedly striking a 32-year-old woman with his SUV, killing her.