Americans have always looked on the Labor Day weekend as one last fling with summer. For most drivers, that once meant a lot of high-anxiety mileage, as they worried about keeping up with traffic while avoiding ticket-happy state troopers.

But no longer. Last year Congress repealed the National Maximum Speed Limit of 55 mph (65 mph on rural interstates and freeways designed for high speeds). Now states can set their own speed limits based on local driving conditions.

For more than 20 years, the Democratic leadership in Congress blocked all efforts to overturn this anachronism. In 1995, though, the tide changed. With their robust commitment to limited government, conservative House and Senate freshmen strongly pushed for a repeal -- and were finally successful when President Clinton reluctantly signed their bold legislation.

Since the repeal, more than 20 states have raised their limits, including seven within a week of the repeal's effective date. Four of those states -- Oklahoma, Wyoming, Nevada and Arizona -- posted a top speed of 75 mph, while Montana eliminated its daytime speed limit for passenger vehicles, reverting to its pre-1974 law requiring drivers to maintain a "reasonable and prudent speed."

The results? Highway patrolmen and state traffic engineers in Montana and in every other state I spoke with -- 11 in all -- report that average speeds have only increased one to two mph. Fatalities have actually decreased in some states. So much for safety advocates' apocalyptic predictions. Patrolmen and traffic engineers -- whose reputations depend on drivers' safety --resoundingly supported the repeal because it permits states to set more reasonable speed limits. According to engineers, the proper method of determining limits is to measure the speed of traffic under ideal conditions. The posted speed limit should be the speed that 85 percent of traffic is traveling. In effect, drivers set the speed limit.

On many highways, the federally mandated 55 and 65 mph speed limits were unreasonably low -- often five or 10, and sometimes 15 mph below this driver-imposed maximum. The feds, of course, set the low limits in the name of safety. Yet, when people drive at the 85th percentile speed, they "are least likely to be in motor vehicle crashes," according to engineer Tom Hicks of the Maryland State Highway Administration. "It's the people who drive much slower or faster who are most at risk." Unreasonably low speed limits exacerbate the risk posed by these slower and faster drivers. Alan Soltani, the chief traffic engineer at the Oklahoma Department of Transportation, says when the driver-set maximum was 75 and the speed limit was set at 55, "drivers weren't comfortable -- some drove 55, some 65, some 75. There was so much variance that accidents increased." When the limit is raised to its proper level, the evidence shows, these dangerous variances in speed start to disappear.

Efforts to enforce unreasonably low speed limits also undermine police effectiveness. In 1978, Congress started requiring the states to certify drivers' compliance with the 55 mph limit or face cuts in their federal highway funds. So highway patrolmen were told to enforce a law that the majority of motorists were breaking -- a law that threatened rather than improved safety.

Indeed, in a 1984 study of the effects of the 55 mph speed limit, the National Research Council found that 29 percent of highway patrol hours were devoted to rural interstates, where only 9 percent of traffic fatalities occurred. This means more dangerous roads -- such as undivided country highways, high-speed two-lane roads and highways running through congested commercial areas -- received less attention.

By requiring states to prove they were enforcing the 55 mph speed limit, the federal legislation effectively reduced patrol presence on non-interstates while increasing the traffic on these roadways. This substantially endangered safety.

"People move off and onto interstates depending on the speed," says Bill Jackman, a representative of the American Automobile Association. "If the speed limit is only 55 or 65, they will move onto a country road that will get them there just as fast. The problem there is that the fatality rate is three times higher when you get off the interstates. Interstates are the safest highways we have." With repeal of the federal limit, states can post more realistic limits that will attract drivers to the safer interstates. The repeal of the national speed limit may even signal new attitudes in Washington. Restoring the states' authority on this issue means trusting them to form safe and responsible policies. And if we can trust the states in this area, why not others?