Shark's back fin mode assaults to car drivers

Amigos:

I don't know if there is another country where this way of assaulting car drivers is being used; in Perú it happens only once in a while, not only over some lonely urban roads but also, and specially, over the driveways between large cities: we call them Shark's Dorsal or Back Fin way, and I show here a couple of pictures of the "instrument" used:

This "fin" is an iron piece, ususally painted full black to minimize its detection, and is usually used during the nights on lonely stages of "long and windy" drives when drivers are less likely able to detect them protruding from the road, like the next picture shows (if you look carefully you will notice the "black fin" protruding some 2-3 inches form the road):

Well, what happens if you run with your car over one of this creative objects is that at least one of the tires of your car will be punctuated and a couple of hundred feets ahead you'll have to stop to repair o change a flat tire; so the criminals will have some men ahead and wait for any inadverted driver who "innocently" will stop in a perfect place to be victimized (to be robbed, kidnapped, etc.); of course the criminals had previously studied the best place to do it, so the surprise is on their side almost always.

What should you do to prevent this?:

• avoid driving alone, especially during the night over unknown or unprotected areas;
  
• be always alert, especially for dark plastic bags on the road (many times they cover the object with them)
  
• have your car's light system perfectly checked beforehand

Finally, if you happen to be at the wheel when it happens:

• never stop on a lonely or dark area ahead;
  
• you should turn as soon as possible backwards (a "U" turn) and forget about ruinning your possibly already flat tire and
• look for a protected and iluminated place where you can safely change or repair your affected tire (s)
• report as soon as possible the incident to the authorities in the area

JSR