1992 study of Photo Radar proposal for DC Capital Beltway
is here:
[link|http://ntl.bts.gov/DOCS/ase.html|[link|http://ntl.bts.gov/DOCS/ase.html|http://ntl.bts.gov/DOCS/ase.html]]
Beware, it's 300 kB or so (140 pages of text)...
It's got some interesting history (e.g., time-and-distance was used to catch speeders in NY in 1902 - times were relayed between officers 1 mile apart), a summary of the legal arguments for and against photo radar, statistics about speeding and accidents on the Beltway, experiences of photo radar use in Paradise Valley, AZ and Pasadena, CA, a small study of photo radar in the VA area, and recommendations and proposed laws for VA and MD.
It's an interesting read.
While they have a survey which says that around 60% of drivers would approve of the use of such a system, and while there are traffic cameras all around it, there's not as yet a photo radar system on the Beltway.
Cheers,
Scott.