If you're plagued by red light or speed cameras, help is available: the red light camera detector. Some are single-purpose devices with GPS and an updatable memory chip. Once loaded with the camera coordinates, they warn when one is approached.
Late last year I gathered samples and tested them over a nine-month period. Here's what I found, the results listed alphabetically.
Cheetah GPS mirror
The Cheetah GPSmirror (the product's trademarked spelling) incorporates a GPS chip, LED display, speaker, switches and other components into a mirror that's designed to slip over the stock rearview mirror. Spring-loaded clamps easily affix it to the stock unit and it's powered by the vehicle's 12-volt system.
The Cheetah is portable, but moving it among vehicles can be a more labor-intensive task than moving, say, a radar detector. Learn more about the GPSMirror...
The Cheetah C100 is a diminutive alternative to the Cheetah GPSmirror. It offers the same features and virtues but with few of the mirror's drawbacks. Its compact case, like the Navalert's, has a matte black finish that stolidly resists glare.
Speaker volume is controlled by a thumbwheel switch while a row of four top-mounted switches handles menu functions. These are chromed, unfortunately, generating a dazzling mirror image of themselves in the windshield during sunlight. Learn more about the Cheetah C100.
The Navalert's case is a dark matte color, the best of the bunch at resisting windshield glare. No provision is made for windshield mounting; it's dash mount-only. A magnetic base must first be stuck to the dash. Then the Navalert sits atop the mag-mount.
This arrangement works well but you only get one shot at choosing a mounting location; the adhesive isn't reusable. I'd suggest a site that's directly in your line of sight, for the pale green display disappears in sunlight and requires concentration to interpret at other times. It's easily read at night, though, and closer to optimal that the others on dark rural roads.
This is obviously a product designed for world consumption, witnessed by no fewer than one dozen time zone settings—GMT plus or minus hours—by its metric distance display and non-U.S. menu items. Learn more about the Navalert.