San Diego and the Lockheed contract team determined where to put cameras based on where they thought the maximum revenue stream was, instead of danger to others. One light -- at an intersection that is frequently gridlocked because it's the most popular route out of the airport, which frequently has out of town visitors -- generated nearly 50% of the revenue from the red light systems.
It was clearly not about safety, but about selectively enforcing laws to maximize revenue. That's why the city stopped doing it.