A coach driver taking 52 children and adults from West Bromwich to Weston-super-Mare for the day lost control of the coach, hit a crash barrier before plunging off the hard shoulder this morning.
Amazingly though no one was seriously hurt.
Chief Inspector Yan Georgiou from Gloucestershire Police said collision experts were investigating the circumstances.
"What's remarkable is the number of casualties and a really important safety message is starting to emerge.
"The passengers were wearing seat belts, without them this could have been a very different picture," he said.