Four people were injured in a frontal collision between two cars on the N99 near Hippolytushoef at around 4:30 p.m. One of the cars ended up on the roadside guardrail. The cause of the crash was not known. All four occupants were taken to hospital by ambulance, and the severity of their injuries remains unknown. Multiple emergency services, including several fire crews and a trauma helicopter, attended the scene. The N99 remains closed, and Rijkswaterstaat says it may reopen around 9 p.m.