Improvements in road policing springs to mind. Due to cut-backs and other factors, traffic police are now virtually non-existent in large tracts of the UK, often only evident in some of the "glamour" areas like motorway duty or making TV programs for Channel 5.
Many years ago all aspects of motor vehicle law were the concern of every police officer at all times, but that has gradually changed. This process first started when parking control was removed from the police and placed first with traffic wardens and later other bodies. Then traffic control was partly shifted to traffic wardens and partly to sophisticated electronic systems like smart traffic lights and junction/speed control cameras.
Then many other areas of policing were broken up into specialised squads and units dealing with narrow areas of law and order, ironically including traffic.
The outcome of these processes are that the great majority of police officers consider anything to do with traffic nothing to do with them, that duty left to a tiny and often almost invisible number.
