Federal regulators are putting pressure on Chrysler to accelerate production of trailer hitches needed to repair an estimated 1.6 million Jeep SUV’s. In June 2013 Chrysler and the NHTSA reported that the fuel tanks in these vehicles are more susceptible to leaks and fire during certain rear impact accidents because of the location of the tank behind the rear axle, slightly below the rear bumper. Chrysler’s repair of installing a trailer hitch for extra protection has been approved by the NHTSA despite criticisms from consumer advocates who say that hitches will only incrementally improve the performance in certain low speed rear impacts. The initial Jeep recall involved approximately 2.7 million vehicles, but Chrysler says that, given the age of some of them, only about 1.6 million remain on the road.

Since the automaker agreed to the recall more than a year ago, there have been at least four rear impact crashes resulting in fires in which three people died, according to NHTSA executive director, Clarence Ditlow, in a July 2 letter to David J. Friedman, the agency’s acting chief.