A bullet-proof vest does not mean you’re bullet-proof. It just means most bullets won’t penetrate the vest.
But some will.
Same with radar detectors. You’ll be less vulnerable – but you won’t be able invulnerable.
Probably the greatest threat – the one radar detectors are least able to protect you from – is so-called “instant- on” radar. The problem isn’t that your detector won’t detect that you’ve been targeted. The problem is not detecting the radar in time to do much about it.
Here’s how it works:
Revenue collector parks on the shoulder or some other such place where – ideally, from his point of view – he can see oncoming cars before they can see him. He waits, finger on the proverbial trigger. His radar gun’s trigger. When he sees you coming, he pulls the trigger and a brief burst of radar emanates from his gun. Just as your radar detector detects the signal, it’s already bounced back to him, giving up your speed. You hit the brakes, but it’s too late.
He’s got you.
Most radar detectors need about 0.8-1.5 seconds (the better units being more sensitive) of radar signal before they’ll alert. The problem is the latest instant-on police radar can hit you with a burst so brief in duration – as little as .016 seconds – that your detector either won’t detect the signal or won’t detect it quickly enough to give you time to react.
Instant-on is most effective on lightly traveled roads, where there’s not much traffic. Because until it’s activated, you will get no warning – no matter how sensitive your radar detector is. And if you’re the only car on the road, the cop activating it has already drawn a bead on you. While radar is by nature diffuse – unlike a laser-based speed detection system – and so cannot tell which car is “speeding,” if you’re the only car around, it’s a difference without a distinction.
Busted.
Instant-on is less effective when there’s traffic in the sense that there are more potential victims. Thus, the chances of it being you are lessened.
There’s also another reason.
Your detector will detect the instant-on being directed at the car ahead of you. Which will give you time enough to cut your speed. This is why it’s wise policy to always find – and follow – a blocker car. Some other guy who is driving at about the speed you’d like to maintain. Let him take the bullet (so to speak) for you.
Laser is another big problem – even more so than instant-on radar because you will get absolutely no warning (the beam is virtually instantaneous) and also because – unlike radar – it is very specific. The light beam doesn’t diffuse as it reaches out to your car. If the revenuer is pointing his rig at your car, there will be no doubt (in court) that it was your car he ID’d as “speeding.”