Guards tested in 1971 were better and stronger than current guards

 

Underride/Override of Automobile Front Structures in Intervehicular Collisions (1971 study)

1971-UnderrideOverride-of-Automobile-Front-Structures-in-Intervehicular-Collisions-1971-study-small.zip

“Properly designed energy absorbing (yielding) underride guard systems can provide the advantages of reduced accelerations and crush of the impacting vehicles, better control of crash energy dissipation, and lower loadings on the truck structure.”

(Lower loadings on the truck structure means the frame and support structures can withstand the forces generated at higher speeds prior to failure.)

“The test results also indicate that the loads imposed on an underride guard are reduced in off-center impacts as a result of less engagement of the full width of the striking vehicle and the tendency for the vehicle to spin out.”

(NHTSA fails to use this 1971 knowledge to render high-speed crashes survivable for offset crashes)

(Guard weight for properly braced stiff guard is much higher than for energy absorbing design, a government agency has lead us to believe this cannot be!)

18″ Energy Absorbing Guard

“The two outboard support are angled to provide increased lateral stability to the system. The weight of this guard configuration was approximately 200 lbs.”

 Energy Absorbing 18 inch Guard18″ Energy Absorbing Guard

18″ Rigid Guard

“The calculated weight of this guard and support structure is 340 lbs. Supporting structure for the bumper includes 3″ x 2″ x 1/4″ vertical tubes welded to the aft surface of the cargo platform and eight 3″ to 5.7″ #I beams angled forward and welded to the trailer frame and cargo bed side rails.”

Rigid 18 inch Guard18″ Rigid Guard with angled extra bracing