REAR-END automobile accidents are common enough, but one particular form is especially lethal. It is the underride crash: the collision in which a car goes under the rear end of a large truck or trailer with such force that the passenger compartment is either crushed or sheared off. Recent hearings before the Senate consumer subcommittee revealed that underride collisions account for an estimated 100 to 200 deaths per year. An official from the Federal Highway Administration said that the crashes "are on the increase."

The subcommittee chairman, Sen. Wendell Ford (D-Ky.) was properly critical of the current standards. As administered by the Federal Highway Administration, they are 20 years old and weak in regulating height and weight requirements. There are no strength requirements at all. Test films made by the Insurance Institute for Highway Safety showed the horrors of collisions when trucks or trailers complied fully with the standards, and even when cars hit trucks at speeds well under 40 miles an hour. William Haddon Jr., M.D., of the institute noted that "both the problem of needless passenger-compartment penetration in auto-truck rear underride crashes, and the availability of solutions to it, have been known for years to both industry and government - yet neither has acted to apply the solutions."

The inaction spans eight years. In 1969, the National Highway Traffic Safety Administration proposed standards that would have required energy-absorbing devices to be hung from the rear frames of trucks and trailers, thereby breaking the impact of in-crashing cars. Two years later, the agency withdrew its proposal; truckers had voiced their opposition. Shortly after, in November 1971, the National Transportation Safety Board issued a report that argued persuasively in favor of the devices. But with the two agencies differing about the need for protection, nothing was ever done.

With the issue again before the public, another decision is pending. Inexpensive and efficient technology is said to be available. If that is so, then all that's needed is a measure of resolve on the part of federal highway-safety officials, based on the general principle that when cars and trucks collide, passengers in cars need all the protection that is available.