VG-2 and Spectre RDD

In some localities, it's illegal to use a radar detector, and many areas have regulations against using detectors in commercial vehicles. Therefore, police have developed "radar detector detectors," referred to as RDD. These devices pick up oscillations emitted by the receivers in radar detectors, and inform police that a radar detector is being used. Many manufacturers now have models that are specially shielded to eliminate most of these emissions, or will shut down when they detect a RDD system in use.

VG-2 is a common type of RDD technology, and it works by detecting the oscillations on a single frequency band. Most detectors today are built to protect themselves from VG-2 detection, but a newer type of RDD technology, known as Spectre, has proven more difficult to circumvent. This is because Spectre operates on several frequency bands and can pick up more emissions from a radar detector. There are detectors on the market now which do offer Spectre invisibility.

Laser Detectors

Laser speed guns determine speed differently than radar guns. A series of light pulses is transmitted, and the difference in time between pulses and reflections is used to calculate speed. This all takes place very rapidly (at the speed of light, as a matter of fact). A single pulse typically requires only a few nanoseconds to transmit and return. The advantages of a laser gun are compelling: the laser light beam is far narrower than a radar beam, allowing more accurate pinpointing of a specific vehicle; and the total time needed for capturing a speed reading is less than half a second versus 2 to 3 seconds for radar.

The drawbacks are also important to note: laser guns are very expensive, they can't be used from a moving vehicle or from behind glass, and accurate aiming requires a tripod or a very steady hand.Despite initial claims to the contrary, a laser gun is detectable. And as the laser beam moves away from the laser gun, it widens and becomes even easier to detect. Vehicle speeds are typically measured at roughly 1,000 feet (1/5 mile); at that distance the laser beam is over 3 feet wide. Many of the laser detectors in use have a working distance of approximately 1-1/2 miles (at that distance a laser gun's beam covers two lanes of traffic).

Factors Affecting Range

According to a Car & Driver study, a significant loss in detection range occurs when vehicles contain windshields with metallic film embedded, and when commercially available tint films are applied.

Radar detection range is most affected by windshields with metallic film solar-barrier treatments, found in Ford products with Instaclear windshields, GM products with PPG and Everclear windshields, and in some high-end imports. In these vehicles, detection capability drops by a startling 95 percent!

Laser detection range is always affected by glass, sometimes losing up to 80% of its sensitivity. It's also affected by tint films — the darker the tint, the more loss. Some tint films contain a metallic layer, and these can reduce radar detection capability by as much as 37 percent.