An exhibition trailer bound for the Black Isle Show came loose and hit a bus during rush hour traffic on a busy north road.
The collision happened at about 8.45am on the A96 Inverness to Aberdeen road at its junction with Duncan Drive in Nairn, near the Gulf petrol station.
It is understood that a trailer was being towed westbound to the Black Isle Show ground at Muir of Ord but become detached from its lorry, before colliding with a coach that was heading east.
Police were called to the scene and inspected the trailer alongside officials from the Driving and Vehicle Standards Agency, according to witnesses.
A towing hitch could be seen on a grass verge close to the incident.
The road was closed in both directions with diversions in place, although some local traffic was allowed to pass via the petrol station.
There was further disruption on north roads yesterday after a caravan had to have a wheel changed on Kenneth Street in Inverness, on the A82 Inverness to Fort William Road, at about 2.30pm.
Meanwhile, the northbound lane of the A9 Inverness to Perth road was blocked at Raigmore due to a broken down heavy goods vehicle at about 4.40pm.
Drivers in the area have been warned to expect delays as the Black Isle Show and the Belladrum Tartan Heart Festival get under way.
More than 20,000 people are expected to attend Belladrum between today and Sunday, and police have asked motorists to leave plenty of time for travelling.
David Haas, Highland Council’s Inverness City Area Manager, said: “Highland Council has worked closely with multi agency partners and the event organisers to provide the best possible opportunity for Belladrum to once again prove to be a great success.
“Special attention has again been given to working closely with the organisers of the Black Isle Show to co-ordinate traffic flow and we would ask that people allow enough time for travel and listen for any announcements.”