Radar detectors and your car insurance

In most states you can use a radar detector for personal use to avoid speeding tickets, and there's really not much your car insurance company can do about it.

A radar detector alerts the driver when it picks up signals emitted by radar equipment that police use to catch speeders. The idea is for the warning to sound before the cop points the radar gun at you.

Ranging in price from about $35 to more than $500, even a pricey model would more than pay for itself if it kept you from getting a ticket and subsequent hike in your car insurance rates.

Like any high-tech gizmo, radar detectors have gotten more sophisticated. Using GPS technology, some of today's detectors can calculate how fast you're going and then adjust their sensitivity to radar signals accordingly. You need long-range sensitivity when you're going fast and shorter-range sensitivity in town.

Some radar detectors provide digital voice alerts, and some can detect laser as well as radar signals. Now that local governments are using speed and red-light cameras, some models come loaded with information about the camera locations, which you can update using a computer and Internet connection. Many of today's radar detectors also work in conjunction with smartphone apps.

Not legal everywhere

Beware that radar detectors are prohibited in Virginia and the District of Columbia, as well as on U.S. military bases. In Canada, they are prohibited in Manitoba, New Brunswick, Newfoundland and Labrador, the Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward Island and Quebec.

In addition, 20 states besides Virginia and the District of Columbia prohibit the use of radar detectors in commercial vehicles.

If you're ticketed for unlawful use of a radar detector as a non-commercial driver, you'll face a fine of up to $300 in the District of Columbia. In Virginia, you'll pay about $100. In Fairfax County, for instance, the fine is $40, and the processing fee is $62.