A crowd helped lift a car off a critically injured rider at the Wiggle Cotswolds Sportive in Gloucestershire on Saturday morning.
The 18-year-old was freed from underneath the Audi A3 by about 15 people after the serious collision, near Guiting Power, in the Cotswolds.
The cyclist was then airlifted to Bristol's Southmead Hospital, reports the Gloucestershire Echo, and is being treated for life-threatening injuries.
Laura Neno, who arrived on the scene shortly after the collision, told the Echo: "Everyone involved was brilliant.
"Some lifted the car off of him and a couple of doctors who were on the ride stayed with him until the medics arrived."
The collision took place yards from a junction on a steep descent on Campden Lane, where riders from all three routes, the 105, 75 and 40 mile routes, would have entered Guiting Power. The descent curves to the right, with a crossroads at the bottom before the Campden Lane ascends again.
Campden Lane, near Guiting Power, Gloucestershire
Riders on the Wiggle Cotswolds Super Series Sportive left Cheltenham Racecourse on Saturday morning between 7.45am and 9.15am.
Firefighters were sent to the scene near the junction of Campden Lane and Critchford Lane, Guiting Power, at around 10.21 on Saturday morning, and remained there for more than an hour.
Gloucestershire Police are appealing for any witnesses who have not spoken to them already to come forward. Anyone with information should contact 101 quoted incident 146 of August 15.