Read This:
http://www.sunjournal.com/story/223522-3/Business/Fire_a_recurrent_peril_in_Jeep_collisions/

And :

http://forums.automotive.com/70/6228262/jeep/jeep-liberty-fuel-tank-fires/index.html

Do they make a stronger rear bumper or what can we do for better protection ??
At least I have the factory skid plate around the gas tank, and I welded the trailer hitch receiver in place, so it is always on..any ideas or after market thoughts?

 

Dude .. stop reading so much ...lmao ... just kiddin'

BUT

nearly all vehicles hit in the rear, at those kinds of speeds are at risk for puncture or combustion.

Cheers,
Luke