Did Congress really do the right thing when it let states increase the speed limit on rural stretches of the Interstate freeway system?

There's room for wondering in view of this week's report from the Insurance Institute for Highway Safety, which notes that as traffic speeds have mounted so has the death toll.In 1987, during the months after 38 states - including Utah - raised the speed limit from 55 mph to 65 mph on their rural Interstates, highway fatalities on those routes rose 22 percent over the previous five-year average for the same months.

By contrast, highway fatalities on other rural routes fell almost 1 percent.

The conclusion seems unavoidably clear: Speed kills. That fact surely can't come as a surprise. After all, the faster a vehicle travels, the less time a driver has to avoid an accident and the greater is the damage done by the resulting impact.

One other point from the Insurance Institute's study also deserves emphasis, since it exposes the folly of the claim that the speed limit has little or no effect on how fast drivers travel.

Immediately after the speed limit was raised from 55 to 65 mph in Virginia, for example, the percentage of cars going faster than 70 mph on rural Interstate highways during the daytime more than doubled, from 7 percent to 15 percent. By contrast, in neighboring Maryland, where the speed limit remains 55 mph, the proportion of cars exceeding 70 mph on rural Interstates during the daytime remained unchanged.

This and other new data clearly show that, although posted speed limits are frequently exceeded, they do exert a strong influence on how fast motorists drive.

Though the higher speed limits save time, they clearly waste lives as well as fuel. Does that kind of trade-off really justify keeping the new 65 mph speed limits?