Tucsonans won't get to decide on banning red-light cameras in the November election because initiative petitions lacked the valid signatures, Pima County officials said Monday.

The measure, proposed by former state legislator John Kromko and a group he called Traffic Justice, needed 12,730 signatures, and the group gathered more than 20,000. A random sampling by the county recorder's office found 55 percent were valid, with a projection from that showing the total number would fall short of the minimum.

Kromko proposed the measure saying the city used red-light cameras not as a means to enforce traffic laws for safety but as a revenue source. City officials said they collect about $680,000 a year in fines from the tickets issued as a result of the cameras.

Officials also said safety has improved at the eight intersections where they are installed. Since the January 2007 installations, the number of crashes at the intersections has gone from 200 to 74 last year, the city reported.