The warning period will last 60 days before enforcement begins.
The switch has now been flipped on some new red light cameras in Center City Philadelphia.
After January 8, drivers caught going through the red light will receive a $100 fine in the mail.
Two new red light cameras are coming to a major highway in Bucks County, and drivers who run the lights could get hit with $100 fines.
The first cameras will go up on Lancaster Avenue at Remington Road.
The warning period ends on July 2. After that, anyone captured on camera running a red light at this intersection will receive a $100 fine in the mail.