Progress Way in Marton was closed following a serious rush hour crash at the junction with Midgeland Road earlier this evening, police said.
The smash, which involved a grey Hyundai, a silver Mitsubishi Outlander, and a blue Vauxhall Astra, left a man in his 'mid to late 50s' trapped in his vehicle, a spokesman for Lancashire Police said.
He was cut from his car by firefighters, though it was not immediately clear which one, while paramedics were on standby to take him to hospital, he said.
A picture shared online later by Lancashire Fire and Rescue service crew manager Simon Hickson showed the wreckage, including the Astra, which had its roof cut off.
The man is understood to have suffered injuries to his legs, and was initially found unconscious, police added.
The accident was spotted by a passing patrol at 5.59pm, who radioed for backup.
The road was then closed between the roundabout in Progress Way and the lights at Midgeland Road.
Nobody else is believed to have been seriously hurt.
An investigation is now underway.