This 2002 report by the California State Auditor shows that 77% of red light violations happen within the first second a light is red. In some cities, that figure is as high as 88%. The report also shows the city of Los Angeles admits one of the key criteria for selecting intersections is "increased revenue" (page 26).

The full report is available in 796k PDF format at the source link below.

Key Statistic:
Percentage of Citations Occurring Within One Second of the Red Light (from page 43)

Fremont*	88%
Long Beach	84%
Los Angeles	86%
Oxnard	73%
Sacramento	82%
San Diego	57%
San Francisco	72%
Average	77%

"Our review found at least two instances where vendors misused photographs taken by red light cameras. In one instance, a photograph that showed a bicyclist being struck by a vehicle in San Francisco was posted in the hallway of the San Diego Police Department." Page 21.