The GPS Angel is designed to warn drivers of red light and speed cameras using an on-board database and GPS. It's a great device... if you don't have an iPhone or other smart phone with a data plan.
Like using AOL to connect to the Internet, this device only exists for people who are afraid or unable to use modern technology but would like to enjoy its benefits. As opposed to just using a free and automatically updating device like Trapster on your smart phone, the GPS Angel plugs into your cigarette lighter and crosschecks your location with the device's internal database. To keep that database updated you gotta plug it into your computer — probably a circa-2000 Gateway.
It's a whopping $99, which may be perfect for your red light-running Grandma.