Traffic headed to Preston has come to a standstill after a car crashed into a barrier on the Guild Way bridge at around 7.20 am.
The crash has affected the surrounding roads with long delays reported on both sides of the river.
Traffic is still heavy and unmoving in some areas.
Lancashire Police tweeted: “We are currently at the scene of a two vehicle collision on the Penwortham flyover bridge.
“Emergency services have attended and the road is closed. We are advising motorists to avoid the area and find alternative routes where possible. We will update you in due course.”
It is understood that the car is still blocking the Preston bound carriage way and recovery vehicles are at the scene.