THIRTY-one tonnes of gravel spilled across the Mary Valley Hwy at Dagun yesterday morning when a truck rolled about 7am.
Imbil police Senior Constable Bill Greer said the truck was hooked to a loaded dog trailer and was on its way from Moy Pocket to Gympie when the driver lost control.
Snr Const Greer said the trailer veered to the left side of the road which caused the truck to flip on to its side and slide about 40m down the road, blocking traffic in both directions.
It came to rest on the passenger's side and lay across both lanes, covering up the width of the road and holding up traffic for four hours.
Snr Const Greer said and the driver, in his 30s, was uninjured and lucky to be alive.
"He had no injuries but was obviously shaken up," Snr Const Greer said.
He said it was equally fortunate no oncoming traffic became tangled up in the single-vehicle crash.
Snr Const Greer said while the Gympie Brooloo Rd wasn't the region's busiest, peak hour hit as drivers on their way to work queued at the mass clean-up.
Police were able to guide traffic around the crash by directing cars, one lane at a time, off the road and on to the grass shoulder.
He said the driver of a small tip truck saw the trouble as it unfolded about 150m ahead of him and was able to stop just 20m shy of the flipped truck and tailer.
"It was lucky there was no (closer) on-coming traffic," Snr Const Greer said.
It took emergency services and assisting crews until 11am to clear the heavy load of scattered gravel from the road and tow the truck and trailer.
Snr Const Greer said the driver and witnesses were being interviewed by police and investigations were continuing.