Surrey Police referred the collision to the IPCC as it involved one of their officers.
The IPCC decided to oversee an externally-managed investigation, which is being carried out by Sussex Police.
Andrew Crabb will appear at Crawley Magistrates' Court on January 29.
More top news
A volunteer on her campaign said to a voter that rival Sadiq Khan was a "liability" because he is Muslim.
A food historian has claimed that pasties made in Cornwall were mainly vegetarian - and the term 'Cornish pasty' was coined in London.
The demonstration is due to take place next Saturday in central London ahead of the "emergency" meeting in Brussels to discuss the crisis.