Sorry, just realised this was posted on the wrong thread.

However some of it still remains valid, especially the comments about ANPR.
Another idea would be resident operated speed camera's are as done in some rural areas. Information gathers is passed on to the police.

Even if a traffic unit just arranged with residents of affected streets to spend an hour or so on the street with residents, lasering cars, and getting a true idea of the speeds people travel down our roads. Then residents would know what a speeding car actually looked like, and the motorists would be aware that something is being done.