Rush-hour traffic was badly affected after a crash between a prison van and a tipper truck.
Police and paramedics attended the crash at 3pm on the Chatham-bound leg of the Wainscott bypass, near the Four Elms roundabout.
An ambulance left for Medway Maritime Hospital just before 4pm carrying a man who suffered minor head injuries.
Tailbacks quickly built up on the busy dual carriageway.
The A289 was closed eastbound just after the junction with the B2000 Cliffe road. It has since re-opened.
No prisoners were on board the van at the time of the crash and no-one was believed to have been seriously injured.