A major incident has been declared after a double-decker bus overturned in a crash involving a motorcycle.
Avon and Somerset Police said the A39 Quantock Road in Bridgwater has been closed.
A spokesman said: “A significant number of police, fire and ambulance units are on the scene and a major incident has been declared.”
Passengers on the bus included workers from Hinkley Point C nuclear power station.
A spokesman for the power station said: “A bus carrying members of the Hinkley Point C workforce has been involved in a traffic incident on the A39 in Bridgwater.
“Emergency services are on the scene and travel to and from the site has been suspended.”
He could not comment on how many workers were involved or whether anyone had been injured.
Emergency services were called at around 6am on Tuesday.
Closures are in place at the junction of Sandford Hill and Quantock Road.
In the early hours of Tuesday, police urged people to “please only travel if it is absolutely essential” as they received more than 100 reports of road-related incidents in five hours.
They said: “Conditions are extremely icy and dangerous due to the freezing conditions overnight and residual water on the road from the past week’s wet weather.”
A total of 53 crashes were reported to police between 6pm and 11pm on Monday, most of them due to the freezing weather causing dangerous driving conditions.
Seven of these incidents were reported to have resulted in injuries, but they are not thought to be serious, police said.
A further 67 calls concerned other road-related incidents.
Superintendent Mark Runacres said: “We are advising the public to only travel where absolutely essential due to the treacherous driving conditions.
“If travel is necessary, we ask the public to take extreme caution and allow additional time to travel.
“We have seen a significantly higher number of road-related collisions and incidents in the past 12 hours, which has increased the demand on police resources.
“We are working with local authorities and National Highways to ensure roads are properly gritted ahead of the rush-hour traffic to improve driving conditions.”