Radar Detectors and Driveway Sensors

Bands, direction and GPS: what a detector actually hears

A detector listens for police radar on the X, K and Ka bands, and some also pick up laser. Ka is the band used by much modern speed radar, while X is rare in many regions and mostly produces false alerts. K band is shared with automatic doors and many cars' blind-spot sensors, a common cause of false alarms. A 360-degree model has receivers facing several ways so it hears radar from behind and the sides, and a GPS receiver lets the unit mute alerts at fixed trouble spots.

Windshield unit, dash cam bundle or driveway alarm

The category mixes three kinds of product, so read the title. Car detectors mount on the windshield or dash and plug into a 12 V socket, and some bundles pair the detector with a dash cam. Driveway alarms, which also use the word radar, sense motion at the end of a drive and trigger an alert; they do not detect police radar at all. Check local law before fitting a car detector: they are restricted or banned in some regions and in commercial vehicles.

Questions about Radar Detectors and Driveway Sensors

Are radar detectors legal?

It depends on where you drive. Some countries and regions ban detectors outright, and many restrict them in commercial vehicles, while other places allow them. Check the rules wherever you will drive, since a detector that is fine at home may be illegal across a border.

Why does my detector keep alerting on the highway?

Automatic doors and the blind-spot sensors in many cars transmit on K band, which detectors also listen on. Look for models with false-alert filtering and GPS lockouts that learn fixed trouble spots, and keep the unit's sensitivity setting suited to city or highway driving.

Is a driveway alarm the same as a car radar detector?

No. A driveway alarm detects motion, such as a vehicle entering your property, and alerts you indoors. A car radar detector listens for police radar signals on the road. Check the title and description to see which type a listing is before you buy.