Traffic cameras generate revenue; do they save lives?

The Cedar Rapids Gazette reported on October 4, 2010 that Cedar Rapids traffic cameras have generated more than $600,000 in revenue in less than seven months,  on pace for an estimated $1 million during the first year of operation.  The estimate exceeds original estimates by more than 25%.

The new data raise a series of questions: 
1)  Why are revenues higher than the original estimate?
2)  What plans exist for the use of the additional revenue?
3)  Most significantly, are the cameras preventing accidents and injuries and saving lives?

The chief of police has reported that, while crashes within Cedar Rapids have decreased about 8% and crashes involving injuries have decreased 12% compared to last year, there is not yet comparable data to determine if intersections and roads where cameras are installed are safer.

No one should want intrusive cameras generating traffic citations just for the sake of additional revenue.  The focus should be on avoiding injuries and saving lives—and data should be tracking the results.  After all, that was the primary justification for installing cameras in the first place.