55 MPH Speed Limit Is Unenforceable and Counterproductive

James Baxter is president of the National Motorists Association, which lobbies to preserve the rights of drivers.

In the fall of 1973, in response to the OPEC oil embargo, President Nixon issued an executive order mandating a 55 mph national maximum speed limit. The following January, Congress made it official and passed a "temporary" one-year continuation of the limit. And so began a 22-year odyssey where reality and rational public policy never crossed paths.

Initially, this law was passed to conserve motor fuels, but it soon became lauded as a safety measure. It was for safety purposes that the law was made permanent in 1975. (It was eventually learned/admitted that the reduction in highway fatalities in 1974 was largely the result of reduced travel. The high fuel costs and recession in 2008 had exactly the same effect, although to a lesser degree, because fuel availability was not an issue, unlike the 1973-74 era.)

Motorist compliance with the 55 mph limit was always problematical and became more so as time progressed. Ticketing binges, threatened financial sanctions, relentless PR, and increased fines and penalties failed to stem noncompliance. Despite increasing noncompliance and increased highway speeds, fatality rates continued to decline, contradicting the folklore that higher speed limits and higher speeds result in more serious accidents.

In 1982, congressional proponents of the 55 mph speed limit, frustrated with their inability to bludgeon the populace into compliance with it, passed legislation commissioning the National Academy of Science to do a "study of the benefits of the 55 mph National Speed Limit." Although the intent was to bolster political and public support for the law, the outcome was to be just the opposite.

While the academy study, done by the Transportation Research Board, labored to put a positive spin on the most ignored law in the nation, it also undermined the propaganda that had supported this law from its beginning. One such revelation was that the law had virtually no meaningful effect on fuel utilization. The TRB researchers estimated that if the speed limit were raised from 55 to 65, national fuel consumption would increase by .018 percent. Saving less than two tenths of one percent in fuel consumption seems a poor tradeoff for putting 200 million motorists through the misery of going back to a 1930s speed limit.

In 1987, a small dose of rationality infected Congress and the states were permitted to raise interstate speed limits to 65—fatality rates continued to decline. In 1995, as one of the few meaningful accomplishments of the "Republican Revolution," Congress repealed the mandatory 55 mph limit in its entirety, and yes, fatality rates have continued to decline.

If this 22-year experiment in politicized "command and control" traffic management had any value, it would be the lessons we should have learned. For example, any student of human nature knows that we should pay attention to what people do, not what they say. In the late 1970s, a Gallup poll reported that 80 percent of the American public supported the 55 mph speed limit. At the same time, a similar percentage of drivers on the interstate system were exceeding that same speed limit. One of the last sates to increase its speed limit was New York. Toward the end of that state's dogged retention of 55, the level of motorist compliance was less than 5 percent. Obviously, painting numbers on a sign and issuing millions of tickets didn't have much effect on traffic speeds. Not that there weren't effects. These were golden years for the radar detector business and small towns along major highways raked in huge amounts of fines, fees, and surcharges.

But what about fuel utilization? Cars going 55 mph get noticeably better mileage than cars going 75 mph. With arbitrary, low, speed limits, that advantage is reduced by interrupted traffic flow, darting, weaving, braking, and accelerating as faster traffic beats its way through slower traffic scattered across all lanes of the highway. Compare this with a highway with a more reasonable and accommodating speed limit where the traffic moves more in sync and there is less braking and accelerating and the slower traffic stays out of the left-most passing lane.

The main reason a lower speed limit cannot have a material effect on fuel consumption, besides being ignored by motorists, is that the preponderance of motor fuels is consumed on streets, roads, and highways that already have lower speed limits and, more importantly, lower speeds. Only 20 to 25 percent of all traffic volume is on highways with speed limits above 55 mph, and this traffic is already achieving superior fuel economy to that of traffic plodding along in urban and suburban areas. (Only 1.2 percent of the nation's 3.8 million roadway miles are interstate highway.) Add in conditions like congestion and bad weather where speed limits become even more irrelevant and it should become obvious that changing numbers on speed limit signs on roads where perhaps 15 percent of all fuel is consumed will not yield the nirvana of "energy independence."

What do you think? Should a national speed limit of 55 mph become law?