Police were called to two single-vehicle collisions on the A24 Dorking Road at Kingsfold, near Horsham, early on Friday, October 10.
In the first, at 6.24am, a car travelling north left the road opposite Shiremark Farm and overturned into a ditch. The driver and passenger escaped unhurt.
In the second incident, at 7.09am, a car driven by a 29-year-old woman crashed into a garden at Myrtle Cottages. A three-year-old girl who was a passenger in the car suffered a serious leg injury.
The Kent, Surrey and Sussex air ambulance attended and the injured girl was flown to St George’s Hospital, Tooting, London.
Officers are investigating the cause of both collisions. One possibility is that they may be linked to a diesel oil spillage in the area.
Anyone who saw either incident, or who may have other relevant information, is asked to email firstname.lastname@example.org or phone 101, quoting serial 156 of 10/10 concerning the collision at 6.24am and serial 178 of 10/10 concerning the collision at 7.09am.