55 m.p.h. -- enforce it or change it

Ever had the feeling that few motorists were observing the 55 m.p.h. speed limit mandated for the nation's interstate highway system? If so, you are right. Statistics compiled by the Highway Users Federation indicate that 70 percent of all motorists on rural interstates ignore the limit. Meanwhile, slightly more than half of all cars on urban interstates are zipping along at higher speeds.

The original reason for lowering the speed limit to 55 m.p.h. was to conserve fuel in the wake of Arab oil cutoffs back in the early 1970s. Motor fuel is now readily available. But since the mid-'70s, it has become increasingly evident that slower highway speeds have helped to decrease auto accidents and in the process may have saved as many as 50,000 persons from fatal crashes.

The rationale for slower driving speeds is still valid. At the same time there is an equally valid argument for raising speeds somewhat in rural areas where distances between cities are long and highways less cluttered with traffic. If one has ever driven the run from Fargo, N.D., to Spokane, Wash., he knows how difficult - and unreasonable - it is to hold the throttle at 55.

President Reagan has long criticized the 55 m.p.h. rule. Thus it comes as no surprise that federal funds for enforcing the limit have been slashed sharply during the the past several years. But cutting enforcement dollars while retaining the law is a rather curious way of instilling respect for the law, especially from a law-and-order-oriented administration.

Would it not be better either to enforce the existing law, if it is to be retained, or change the limit to reflect driving conditions in rural and urban areas? The 55 m.p.h. limit still makes good sense in densely populated urban belts, while a slightly higher speed seems appropriate in rural areas. In any case, why retain a law that is neither followed nor enforced?