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Earth Matters: Slower speeds increase fuel efficiency and save lives

Challenging problems seldom have simple solutions.

So when the first energy crunches came to the United States in the ’70s, we came to realize that the problem had to be confronted on multiple fronts.

We were shocked into action by oil embargoes in 1973 and again in 1979. For the first time in many people’s memories, gasoline and heating oil prices shot up in price as supplies dwindled.

The presidents at the time of the two embargoes, Republican Richard Nixon and Democrat Jimmy Carter took steps to reduce the amount of energy we were using in the United States. Many of their efforts focused on energy used in transportation, including increases in fuel efficiency standards. As a result, automobile fuel efficiency rose in the aftermath of both energy crises.

But energy consumption in cars was not just related to the efficiency of the engines and the size of the cars. Speed was also a factor. Most cars reach the peak of their efficiency at a speed between 50 and 60 miles per hour. Studies would show a 17 percent increase in fuel economy when speed is reduced from 70 to 55 mph.

This prompted consideration of a national speed limit of 55 mph. The limit was ultimately invoked by the Emergency Highway Energy Conservation Act in 1974. The energy savings projected by the change was less notable than hoped, however, because compliance and enforcement were lax.

Still, it was one of several measures taken to reduce reliance on foreign oil.

It had an extra benefit, too. Auto accident deaths dropped significantly, falling more than 20 percent between 1973 and 1975. For the first time, the death rate per mile dipped below four fatalities per 100 million miles driven.

But energy prices went down by the mid-’80s, and Ronald Reagan lowered the efficiency standards. The appetite for a national speed limit faded as well, and fuel efficiency numbers, in turn, plummeted.

Even with higher speed limits, a host of safety enhancements became standard features on automobiles, and death rates continued to trend downward. Beginning in 2003, highway deaths went down all but one year. That is, until 2015.

The rate rose by 11 percent in 2015 and, for the first time since 2007, went over 40,000 deaths in 2016. With legitimate concerns over driving under the influence and distractions from electronic devices, the speed factor is sometimes overlooked.

But speed matters. A 2009 study highlighted in the American Journal of Public Health showed that increases in speed limits accounted for a 3.2 percent increase in highway deaths overall and a whopping 9 percent increase on rural interstates.

Just like here in Pennsylvania, the last few years have seen significant speed limit increases across the country. Several stretches of highway in Blair and surrounding counties have seen increases in speed limits.

While widespread support for a 55 mph limit seems unlikely, many have advocated for a middle ground on speed limits. Such moderation would save both lives and natural resources, while also decreasing air pollution and greenhouse gas emissions. Perhaps it will take us a bit longer to reach our final destinations, but more of us will live to tell the tale.

John Frederick (jfrederick@ ircenvironment.org) writes on environmental topics every other Saturday.

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