A 14-year-old boy from Chorley remains in a critical but stable condition in hospital after being knocked from his bike on Friday night.
Police said he was thrown from his bicycle in Myles Standish Way, near to Bolton Road, when he was hit by what police believe was a blue Audi A3, which did not stop.
The teen was taken to Manchester Children's Hospital with serious head injuries, where he remains.
Sgt Marc Glass from Lancashire's road policing unit said: "My thoughts are with the boy and his family at this difficult time.
"If you witnessed the incident, or have information which might assist the investigation, please make contact with us."
A witness said Myles Standish Way was closed for 'some time'.
A 26-year-old man from Chorley was arrested on suspicion of causing serious injury by dangerous driving, and failing to stop.
He was later released under investigation.
An Audi was seized and was set to be forensically examined.
Information can be reported by calling police on 101, quoting log reference number 1579 of Friday, June 1.