A pedestrian was seriously injured in a collision with a car near Arlesey on Wednesday night.
Police are appealing for witnesses and information after they were called to Arlesey Road at 9.58pm following a collision between a white BMW and pedestrian.
The ambulance service also attended the incident.
The road was closed while officers worked at the scene and reopened at around 3.15am.
Contact Herts Police via 101, quoting reference ISR 874 of March 6.