A red light camera at Chain Bridge Rd. and Lee Highway in Fairfax County. (Larry Morris/The Washington Post)

The start of ticketing ends a 30-day period when only warnings were issued to violators. The cameras will operate 24 hours a day, photographing every red-light runner, police said.

Each violation will be reviewed by the Alexandria Police Department before a ticket is issued, police said.

The cameras are located at the following intersections:

•South Patrick Street and Franklin Street

•South Patrick Street and Gibbon Street

•Duke Street and South Walker Street