CB radios were once the fad for tipping other drivers about speed traps. But the CB is so ’70s.

Enter the modern-day replacement, Trapster—a free app for smartphones that can give drivers advance warnings of speed traps and red light and speed cameras.

Trapster’s database includes more than 1.5 million reported traps around the world. When your iPhone or other GPS-equipped smartphone gets within half a mile of one, you’ll hear a voice warning and the spot will be marked on a moving map. The warning distance can be set from one-fourth to one mile.

When you see a trap, you can add it to the Trapster database with the push of a button. Other users can confirm the location, which helps make the map more accurate. A data plan is required for your smartphone to send the information to the company’s server.

But not all the reports come from drivers who spot the traps. In Texas, the Travis County Sheriff’s Department (Austin area) is entering enforcement locations to encourage safe driving. According to Trapster, deputies also upload other information such as road closures, traffic jams, accidents and dangerous intersections.

I’m impressed by the broad range of phones and operating systems supported by Trapster. It runs on the iPhone as well as Android, Blackberry, Nokia, Windows Phone and Palm devices, plus some Garmin and Tom Tom GPS units. If you don’t have one of those, you can get text message alerts, or use Trapster’s website to print out directions that include the locations of speed traps and enforcement cameras.

Trapster isn’t perfect. Where I live, it shows a red light camera where there’s no light at all. The information will only be as good as the number of people who actively use it and keep the maps updated. The app has more than four million users.

Also, some law-enforcement officers have expressed concern that such apps can be distracting to drivers.

My other problem with Trapster is the company’s terms and conditions, which users must agree to when they register on the site. Now, I usually don’t even read these. But I’d heard there was something particularly onerous in Trapster’s agreement—and it’s this. 

If you knowingly don’t provide correct, current and complete information while registering or using the site, you agree to pay Trapster $25,000.

I asked Trapster’s Stefanie Frederick why this was part of the agreement, and she replies, “As you know, most companies have privacy notices or terms of use pages… that being said, the policy is just saying that there are penalties if a user maliciously uses Trapster on purpose. But we hope that never happens.”

For some reason, that condition still bothers me. And while the company can “hope that never happens,” users have agreed to pay $25,000 if they report false information on the site. That could make a free app pretty expensive.

If you can live with the language in the terms and conditions, Trapster is a roadworthy app to take along on your travels.