It happened on the B3081 near Verwood - he had to be cut free by firefighters.
Officers Sacked Over Facebook Posts
A Hampshire police officer is one of those sacked after posting a racist comment - two Dorset special constables quit after complaints.
At least two officers were sacked, seven quit and 150 faced disciplinary action after posting inappropriate photos or comments on Facebook in the last four years.
Officers used the popular social networking site, which has 30 million users in the UK, to harass former partners and ex-colleagues, to comment on others' wives, and to suggest they had beaten up members of the public during protests.
Some even revealed details of police operations, tried to befriend victims of crime, or were caught in inappropriate photographs, forces said.
The details, released to the Press Association following a request under the Freedom of Information Act, come as a review into police corruption found there was a 'significant blurring' between officers' personal and professional lives on social networking sites which risked damaging the service's reputation.
One officer with the Hampshire force was dismissed without notice in 2009 for posting a racist comment on Facebook, the force said. No other details were released.
The figures, from 41 of the 43 forces in England and Wales, cover between 2008 and 2010, but a second officer was sacked earlier this year for referring to another officer as a 'grass' and a 'liar' on Facebook and harassing a female colleague.
Seven other officers - two special constables from the Dorset force and one officer from each of Bedfordshire, Cheshire, Essex, North Wales, and South Yorkshire - resigned following complaints, the figures showed.
The South Yorkshire officer resigned following an allegation of improper disclosure of information on Facebook, while others posted inappropriate comments or pictures.
Another officer, Pc Nestor Costa, of Devon and Cornwall Police, was fined three days pay in 2008 after he called for violence against suspects in custody.
In all, a total of 187 complaints were made against officers over their use of Facebook, with nine officers being given final written warnings, 47 given written warnings and one given a formal warning.
A further 88 were subject to management action, received guidance or words of advice, while 32 complaints were either withdrawn, found to be unsubstantiated or led to no further action.
One disciplinary outcome in Leicestershire, following comments made on Facebook, was withheld by the force.
Roger Baker, who led a review into police corruption for Her Majesty's Inspectorate of Constabulary (HMIC), said: "Social networking is seen as a risk by all forces and authorities, but there are limited or inconsistent policies around what is acceptable, what you should do, what you shouldn't do.
"We found a significant blurring between people's professional lives on social networking sites and their private lives which may be in the public domain and private lives which probably should remain extremely private."
The Association of Chief Police Officers (Acpo) said that while the service recognised the widespread benefits of social networking sites, it"also understands the risks relating to compromise, operational effectiveness and repetitional damage" .
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