A Honolulu man participating in the California Mille vintage car tour was killed Tuesday in Mendocino County when his 1939 V-1 Jaguar crashed into a tree near the shoulder of Highway 128, the CHP said.

The man, whose name and age were not released by the CHP, was driving the white Jaguar east on Highway 128 near Navarro about 2:30 p.m., when for an unknown reason he drove off the road and onto the dirt and grass shoulder until slamming into a large tree, the CHP said.

The man was not wearing a seatbelt and was partially ejected from the vehicle, according to a CHP collision report. The front right portion of the Jaguar struck the tree.

A passenger in the vehicle, Ai Origake, also of Honolulu, received major injuries. Orikake was wearing a seatbelt. She was transported to Santa Rosa Memorial Hospital and reported in serious condition Tuesday night.

The four-day California Mille, now in its 27th year, is one of the world’s premiere classic car touring events, taking participants on 1,000 miles of California’s back roads.

CHP officials do not believe alcohol was a factor in the accident.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @renofish.