Even though a radar detector has the ability to detect laser guns on
some occasions, by the time you detect the laser gun, it's already
too late - the gun has your speed. And that's assuming your detector does
actually pick it up in the first place.
You see
unlike a speed radar "beam", a speed laser "beam" is much more tightly
focused, with very little of the "laser pulses" going past the car that is
actually being targeted.
At 100m from
the car, the diameter of the laser beam is only 30cm in diameter!!
At 300m from
the car, the diameter is a mere 90cm
So if the
laser is aimed at the centre front of your car, there is actually little
chance of the beam spilling over your bonnet and hitting your radar detector
mounted on the windscreen.
Here's a
view from the front at the diameter of the laser beam at 100m, 200, and 300m
100m
200m 300m00m00m
You can see
from this illustration, that at close ranges, the beam may not even strike
your radar/laser detector when mounted on your windscreen, thereby
failing to alert you when you car is targeted.
Here is a
picture viewed from the scope of a LTI Ultralyte laser gun at 100m,
200m and 300m:
Note: the
latter pictures above are blury because we've zoomed in on the photos to
show you proportionally the same size car each time.
Again, you
can see there is no dispute, the target area is smaller than the actual size
of the car. This is why you are not guaranteed to get an alert from
your radar detector when your car is targeted at close range.
So the first
problem with detecting laser is that your radar/laser detector may not even
go off. The second problem is that even if your detector does go off,
the laser gun usually has your speed in less than 1 second!
Watch the
video below, and see how fast the laser gun gets a speed reading:
Notice when
the fifth car is targeted, it doesn't give a reading immediately
because the laser is aimed at the windscreen (not a good reflective surface
to bounce a laser signal back), but once the laser is shifted down towards
the front of the vehicle, a reading is obtained.
In the above
video your radar detector would have alerted on laser (since the laser gun
was swept across the windscreen) but since a speed reading was still
obtained so quickly you still wouldn't have had time to brake.
Inspired by
Bob's (The Veil Guy) laser detection tests in 2006, we decided to test a few
newer radar detectors against the most common laser gun in Australia - the
LTI Ultralyte.
We sat the
target car at ranges between 25m and 300m and set up the radar detectors
mounted both at the bottom (middle) of the windscreen, and at the top of the
windscreen.
We then
proceeded to fire three shots across the front of the car, targeting the
right side of the car as viewed through the laser gun (the passenger's headlight), centre mass and
finally the left side as viewed through the laser gun (the driver's headlight).
We then noted if the radar detector alerted to the laser hit each time.
