Two men have been taken to hospital after a car hit a pedestrian on Shepherds Way at the junction of Lyons Lane.
Emergency services were called to the busy road at around 11.45am on Thursday, February 8.
Police say several road closures have been put in place around the area and on the roundabout.
An Ambulance Service spokesman said: "A passing ambulance called in the accident as it was making its way on to another incident.
"A male pedestrian in his mid 50s was taken to Royal Preston Hospital with traumatic but none-life threatening injuries.
"An elderly man who was in the car was taken to Chorley Hospital."
Traffic is described as "heavy" in the area and police are advising drivers to seek alternative routes.
A spokesman for the police said in a Tweet: "We are currently dealing with a Serious RTC on Shepherds Way, Chorley at the junction with Lyons Lane.
"Traffic is very heavy due to road closures. Please avoid the area if at all possible."
Police say the car is in the process of being recovered.