Authorities are investigating the possibility that the driver who fatally struck an El Tour de Tucson cyclist had a medical problem before the crash.
The 78-year-old man was driving eastbound on the Interstate 10 frontage road near Sunset Road when he crashed into cyclist John Henderson who was riding in the designated El Tour bike lane around 5:20 p.m. Saturday, according to the Arizona Department of Public Safety.
Henderson, 59, died at the scene.
The driver was taken to the hospital for evaluation and treatment.
"The investigation is on-going with the possibility that the driver might have experienced a medical condition," Officer Raul Molina, a DPS spokesman said in a news release.
Paramedics from Northwest fire tried to resuscitate Henderson and evaluated the driver.
"We believe (the driver) suffered a medical emergency that caused him to lose control," said Capt. Adam Goldberg, a Northwest fires spokesman.
Goldberg could not release details about the medical emergency.