From time to time we've had comments about the significance of people being arrested after a crash and I've suggested that part of the reason is to get access to the tape recording facilities for interviews, rather than the cumbersome alternative which involves contemporaneous notes. This BBC News item, which is about police custody suites being closed, either permanently or for maintenance, includes comment from a defence solicitor about clients going voluntarily to police stations for interview by appointment and having difficulties.
Caroline Woodley, a defence solicitor working in the north of the county, told the BBC: "Chelmsford was closed today [Tuesday] due to the cell buzzers not working.
"This means officers having to travel to other stations and some officers have been just deployed as a taxi service ferrying people between the two.
"Voluntary attendees at Colchester police station are finding it impossible to get into custody. We are obviously having to travel further afield which will in turn cost the taxpayer in legal aid.
"Last week my colleague and a police officer gave up trying to get into custody to do an interview and went to the client's house where a contemporaneous note interview was done instead." (My emphasis.)
http://www.bbc.co.uk/news/uk-england-essex-39196499
Perhaps it goes a little way to explain why investigating near-misses in headcam footage isn't a top priority.