Spirited driving, speeding, scofflaw, or just “Sorry officer, I had no idea”.  How ever you want to describe it there are speed limits and there are drivers that exceed those limits.  Depending upon what road or highway you look at, over 90% of drivers exceed the posted limits.  Not you, you say?  Perhaps, but as we get familiar with our vehicles, the same routes to and from, we bring our speeds up to something that moves us along efficiently and usually this is higher than what the regulations allow. 

Often we get caught up in the flow of the traffic around us or we know the area so well that doing 35 in a 25 zone doesn’t seem excessive anyway.

But the limits are out there and often enough we get an unpleasant reminder when the police pick our favorite avenue or highway to start enforcing those posted limits.  After World War II the military technology of RADAR was applied to speed enforcement on the highway with units that were limited in their range and flexibility.  Some of the first ones were only practical if the unit was stationary.  The emitter and receiver was an obvious give away.  It would be attached to the car’s door and look like a 10″ diameter spotlight with a green opaque lens facing the traffic.  It was still effective and spurred counter measures on the part of the driving public.  The most famous was the Fuzz Buster.  It was a black box that sat on the dash and plugged into the car’s cigarette lighter.  It had an on/off switch and squelch dial.  It was as primitive as what the police used, but for drivers it was a small miracle.  Paired up with a CB radio you felt almost invincible.  At least for a couple of years.

As we know oh so well, technology moves on and so did the speed monitoring technology that the police used.  The counter technology kept up and often exceeded what the police had.  The wave lengths that the police were authorized by the FCC to use (yes, even the police have limits to observe) started as X band, then K band.  Later Ka band was added.  This last one allowed extremely fast switching on of the radar gun (part of the evolution of form).  The one good thing about this technological change was that instead of blasting every vehicle and thing on a roadway with microwave energy constantly, the officer would observe visually the road, spot a suspect and engage the technology to confirm his suspicion.  At least from a legal standpoint this was an improvement since it meant that the officer was actually establishing probable cause prior to confirming the speeding infraction.  This also meant that it was also very difficult to develop a counter technology that would be effective.  Sure, you might pick up the signal if the officer was aggressively using his radar gun on vehicles ahead of you, but if not, you would find yourself in that embarrassing situation of trying to talk your way out of a ticket.

Yesterday USA Today reported on a technological development that could be the next hope for the 90 % of us that just happen to exceed the posted speed limits.  It is a microwave invisibility cloak.  Described by David Smith of Duke University, it diverges from the current technique of absorbing microwave energy to one of bending the microwave energy around an object.  The prototype creates an electromagnetic mirage around objects that bends the microwaves enough to no longer reflect them back, but allow them to continue on the the next object. 

The current stealth technology used on things like military aircraft involve coatings that are much like a “fur” with hair that is the same as the wave length being used by radar to scan with.  That way most of the radio energy gets trapped within the “fur” and is not reflected back.   It is the reflecting back of the microwave energy that tells the police radar gun what speed a vehicle (or other object) is traveling at.  As the energy bounces back its frequency changes if it moves toward or away from the radar gun.  That change is calculated and produces a speed reading. 

If you’ve ever heard a fire truck or ambulance coming toward you and then passing by, you noticed the change in pitch of the sound of the siren.  If you were in the ambulance you would not have heard any change in the pitch of the siren’s wail.  As the ambulance approaches you the sound waves are compressed and you hear the pitch raise and when the ambulance passes the waves are stretched out and the sound drops in its pitch.

With the technology of the microwave invisibility cloak being prototyped by Duke researchers, you might be able to drive a car that microwave energy from a radar gun passes harmlessly around.  The officer would see you, but the radar gun would see nothing.  While radar jammers have been used they are definitely illegal as broadcasting of radio energy is strictly regulated by the FCC, this is a strictly passive technology that would not be under FCC’s jurisdiction.  Things could get interesting.

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1 Response to Stealth

  1. Pingback: Airline Fuel » Stealth Jim’s Garage

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