oos E-Newsletter #250: The Ghosts of 1973


The year was 1973. British rockers Pink Floyd, Led Zeppelin and The Who were battling it out on the top of the charts. That year also marked the beginning of the OPEC oil embargo, and this past October 17th signified the 40th anniversary of that seminal event. Two months after the embargo took effect, Congress passed, and President Nixon signed, the 55 mph National Maximum Speed Limit (NMSL), ostensibly as a fuel conservation measure.

Even though 55 was repealed completely in 1995 (with the oos playing a leading role, of course), the legacy of that misguided, ineffective and abusive policy persists.

Here in Wisconsin, our state Legislature is finally addressing our outdated 65 mph interstate speed limit, thanks to Representative Paul Tittl, who introduced a bill to raise freeway and expressway speeds to 70 mph. At Representative Tittl’s request, the oos testified at a public legislative hearing in support of the original bill (Assembly Bill 389).

Since then, AB 389 has received much public scrutiny and was eventually passed by the Assembly in an amended form. Many in our state’s commercial trucking industry opposed the measure and pushed for a split speed limit amendment (trucks at 65, passenger vehicles at 70), which eventually made it into the final version of the bill. AB 389 now moves on to the Senate, where it could still see more amendments.

The trucking interests have also opposed the bill on safety grounds. A spokesperson for trucking firm Schneider National was quoted as saying: “In no event should the speed limit for commercial motor vehicles be increased. As speed limits rise, so do death tolls on our highways.”

He went on to cite findings from a 2006 National Cooperative Highway Research Program (NCHRP) study that claimed significant increases in highway fatalities resulting from higher speed limits. He didn’t point out the study authors made several startling admissions that would seem to mitigate their findings:

  • Most of the crash data analyzed comes from one state – Washington.
  • Increases in posted speed limits have only a slight impact on actual travel speeds.
  • The direst predictions of negative safety consequences from the 55 mph repeal have not come to pass.
  • Some researchers have not found any significant changes in crash experiences on roads with increased speed limits.
  • Any real negative effects of increased speed limits, if they exist, have likely been offset by other factors such as safer roads, safer car designs, etc.

These points read more like they came from the oos, then from another “Speed Kills” study. And the truth is that as highway speeds have increased since 1995, overall highway fatality rates have fallen 36 percent and interstate fatality rates 33 percent through 2011, according to FARS NHTSA data.

During our testimony on AB 389, we pointed out that five comparable Midwestern states have already increased their interstate speeds to 70 mph. Four of the five (Indiana, Michigan, Minnesota and Ohio) have achieved lower highway fatality rates than Wisconsin, according to FARS NHTSA. The only exception is Iowa with a fatality rate slightly higher than Wisconsin’s. Minnesota has had a 70 mph limit since 1997 and also has the lowest fatality rate of the entire group. So much for Speed Kills.

The trucking lobby has also raised the canard that slower speeds lead to significant fuel savings. (Sounds a lot like 1973 again, doesn’t it?)

Most experts have agreed in the past that the optimum vehicle speed for highest fuel efficiency is somewhere between 50 and 65 mph, with most vehicles peaking in the 55 to 60 mph range.

The variance is caused by differing engine efficiency and drag (wind resistance) coefficients. When the 55 mph National Maximum Speed Limit was enacted in 1973, federal officials predicted a 2.2 percent savings in gasoline consumption. Instead, the Office of Driver Research in the U.S. Dept. of Transportation found the fuel savings to be 1 percent, and some independent studies determined the savings to be a much lower 0.5 percent.

With today’s more efficient engines and aerodynamic designs, any claimed fuel savings between different speeds should be scrutinized carefully. A critical factor in this discussion is the efficiency of traffic flow. Traffic is at its smoothest level when vehicles are streaming at near-identical speeds. Congestion, lane changes, and sudden braking and acceleration are kept to a minimum. That optimum traffic speed has been determined to be the 85th percentile of free-flowing traffic. Whether that speed is 55, 65 or even 80 mph (as it is on some interstates), that is the most fuel-efficient speed at which to travel. It turns out to also be the safest speed to travel.

If the oos had been around in 1973 to point all of this out, who knows how things would have turned out?  Ponder that the next time you listen to The Dark Side of the Moon.

Editor’s Note: Not all trucking organizations support lowered speed limits or split speed limits. Our friends at the 150,000 member Owner-Operator Independent Drivers Association (OOIDA) have long supported properly set speed limits and have vigorously opposed split speed limits as unsafe and unnecessary. The oos wishes to congratulate OOIDA on its 40-year anniversary. 

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