A Napa bicyclist was struck and killed Thursday evening by a Calistoga woman who told a CHP officer that she fell asleep behind the wheel of her car moments before the deadly accident.

Cammie Mutz, 20, was traveling southbound at about 55 mph — the speed limit — when she veered off Silverado Trail near Yountville Cross Road around 6:30 p.m., the CHP said.

She struck Napa resident Alfredo Hernandez Pedroza, who was riding his bicycle along the popular Napa Valley road.

Mutz's Ford continued off the road before it came to a stop at a hillside, authorities said.

Pedroza, 56, died at the scene, leaving his crumpled Trek bicycle behind.

His son, also named Alfredo Pedroza, a Napa City Council candidate and manager of Redwood Credit Union branches in Sonoma and Glen Ellen, told the Napa Valley Register that his father had been training for a 100-mile race.

His father, who worked as a manager for a vineyard management company, had gone on a 50-mile bike ride to Calistoga and back after a full day at work Thursday, Pedroza told the Register. He was riding home when he was hit.

Mutz was said to be extremely distraught in the wake of the accident and was transported to Queen of the Valley Hospital for evaluation, as a precaution, the CHP said.

Authorities were still investigating the crash but said alcohol did not seem to be a factor.