A Glen Ellen man was arrested early Saturday morning on suspicion of driving under the influence of drugs after he veered off Watmaugh Road near Arnold Drive and crashed his vehicle into a tree, injuring both himself and a 14-year-old passenger.

Alfredo Miranda-Rivas, 23, was driving a 2012 Mazda 3, headed west on Watmaugh Road when, shortly before 5 a.m., he suddenly crossed the eastbound lane and went off the highway, according to the California Highway Patrol.

The Mazda slammed head-on into a tree. Miranda-Rivas and the passenger, from Sonoma, sustained major injuries and were transported to Queen of the Valley Hospital in Napa.

Police said neither the driver nor the passenger were wearing seat belts. Miranda-Rivas was arrested at the hospital on suspicion of driving under the influence of drugs, according to a CHP report.