Heavy, queuing traffic was reported both ways but the road has since been cleared.
Two cars were left heavily damaged after the crash. Sussex Police said at least one person was treated for minor injuries.
A spokesperson for West Sussex Fire & Rescue Service said: “This afternoon we were called to a road traffic collision on Western Road, Lancing.
“Joint Fire Control mobilised fire engines from Worthing and Shoreham and heavy rescue tenders from Worthing and Crawley to the scene.
“Upon arrival crews found two people trapped in a car by the junction with Brighton Road. Firefighters removed them both from the vehicle.
“Sussex Police and paramedics from the South East Coast Ambulance Service were also in attendance.”
Fire crews left the scene at around 2.30pm.