A double-decker bus had its roof ripped clean off when it struck a low bridge.
The vehicle hit the bridge in Charlton Road, Andover, Hampshire, at about 09:45 GMT, leaving the roof on the road behind it.
Police said no injuries had been reported and the road was currently blocked.
Bus operator Wheelers Travel said the vehicle was out of service at the time and staff were on the scene carrying out an investigation.
A witness, who did not want to be named, said she was walking on the other side of the bridge with her 10-year-old daughter when she heard an "almighty bang" behind her.
"We jumped and turned around. The bus just kept going quite fast like nothing had happened. Things were falling off it," she said.
The witness said the bus came to a stop about 150m (490ft) down the road.
In 2008, a double-decker bus had its top ripped off when it hit the same 3.5m (11ft 9in) bridge under the A343. Again, no-one was injured.