People in West Hendon Playing Fields saw an air ambulance land on the green space before 4.30pm today (July 1) following the crash.
Medics were called to Park Road and treated a man at the scene before taking him to hospital.
His condition is not known at this time.
A London Ambulance Service spokesperson said: “We were called today (Tuesday) at 4.17pm to reports of a road traffic collision in Park Road, West Hendon.
“We sent resources including ambulance crews, clinicians in response cars, an incident response officer, an advanced paramedic practitioner. We also dispatched London’s air ambulance.
“We treated a man at the scene before taking him to a London major trauma centre.”
