Rickmansworth Road in Pinner was closed off for over seven hours yesterday following a collision shortly before 6pm.
Emergency services rushed to the scene, including two ambulances, as a man was injured in the collision.
The H11 bus route was diverted as police cordoned off the road. The road eventually reopened at around 2:30am this morning (7 June).
A London Ambulance Service spokesperson said: “We were called at 5.56pm yesterday (6 June) to reports of a road traffic collision on Rickmansworth Road, Harrow.
“We sent two ambulance crews to the scene, where our medics treated one man before taking him to hospital.”