Mr. Kadet was "an avid road biker for more than 35 years" and an active participant in organized rides, including many 100-mile rides, wherever he lived, relatives said.
The accident left him with a severe brain injury and unconscious when he was admitted to Stanford Hospital for emergency brain surgery, deputies from the San Mateo County Sheriff's Office said.
Mr. Kadet had "appeared to be in control of his bike," a witness told the deputies. He was wearing a helmet and had a regular Sunday morning routine of a 25-mile-to-40-mile bike trip, deputies said.
According to the witness, who told deputies that she saw the accident in her vehicle's rearview mirror, Mr. Kadet was in the bike lane when his bike began to wobble, and he fell over into the lane of traffic.
Representatives from the Santa Clara County Coroner's Office confirmed Mr. Kadet's death but declined a request for the cause of death.
Mr. Kadet's career was in finance, beginning with General Electric Corp. and moving on to several positions as chief financial officer for Silicon Valley early-stage and start-up technology companies, relatives said.
He is survived by Carol Kadet, his wife of 45 years; daughter Robin of Pawlet, Vermont; sons Ken of Minnetonka, Minnesota and Greg of Tampa, Florida; two brothers in Seattle; and six grandchildren, relatives said.
A memorial service has been held. Donations in Mr. Kadet's name may be made to the Peninsula Temple Beth El Brotherhood at 1700 Alameda de las Pulgas in San Mateo, or a charity of the donor's choice.