Chrysler Group is planning to install trailer hitches on 1.56 million Jeeps as part of a settlement over a recent row with the United States National Highway Traffic Safety Administration. The two entities were recently in a dispute after the carmaker refused a request by the regulator to recall this month 2.7 million 1993-2004 Jeep Grand Cherokees and 2002-07 Jeep Libertys due to fire risks over rear collisions.
Chrysler, however, warned that trailer hitches may not be effective for rear-end crashes above 50 mph. Matthew Liddane, a Chrysler vice president, wrote to NHTSA that the trailer hitch "cannot, and will not, mitigate the risk" of the high-energy rear collisions identified in the regulator's recall request letter.
Bob Sheaves, a former Chrysler design engineer, agrees with Liddane's letter, telling Automotive News that the hitch could only provide little protection in high-speed, high-energy crashes of the type identified in NHTSA's request. He said that during such crashes, too much force is applied to the material and will exceed its yield strength.
US Transportation Secretary Ray LaHood told The Detroit News last week that he was "absolutely" satisfied with Chrysler's modification. In a statement to Automotive News, NHTSA said that its believes that that risk of post-crash fire and fuel leak incidents would be mitigated by Chrysler's planned remedy.
The regulator noted that in some cases, the energy involved is so extreme and the structural damage so severe, leading to a possible fuel leak or fire as a result. NHTSA said that the purpose of the remedy is to reduce the possibility of "damage to the fuel system that results in a fire or leak," noting trailer hitches may be most effective in lower- to medium-speed crashes." [source: automotive news - sub. required]