What you really save when you drive 55

Back in 1974, the National Maximum Speed Law was introduced to cap speed limits at 55 mph. Signed into law with the goal of saving on gasoline usage, its opponents certainly outweighed its supporters. Some states, refusing to comply with the rule, independently decided to subvert its intent by giving only nominal fines for speeding or even just overlooking tickets for speeding if it was within an acceptable range above 55 mph.

This March celebrates the 40-year anniversary of this controversial law. Below is a history of the bill and a look into how much fuel is saved dependent on the speed you decide to travel.

Double Nickel:

Aimed at dropping gasoline consumption by 2.2 percent, this law was widely criticized by most states. Previous to this law’s existence, all states had the right to impose their own speed restrictions. When the law was implemented, some states had to either raise or lower their current limits to comply with the rule. History reports, “The act also prohibited the Department of Transportation from approving or funding any projects within states that did not comply with the new speed limit. Most states quietly adjusted their speed limits, though Western states, home to the country’s longest, straightest and most monotonous rural highways, only grudgingly complied.”

The impact of this law on overall driving safety is not certain. Common sense would argue that the slower you drive, the less chance there is to get into an accident. However, the Cato Institute indicated otherwise. Initial reports after the rule’s implementation indicated a fatality reduction by 15 percent. That was simply a favorable figure being correlated with the law without much supporting evidence. Proper reporting would need to include stats such as type of road, road conditions, car types, traffic patterns, traffic volume, and driver age.

Gas Efficiency:

Many articles have been written explaining the costs and benefits of a speed limit and what it does to fuel economy. Most of them state that an average car’s gas mileage decreases once you get past an optimal speed (in the 55 mph to 60 mph range). It’s also obvious that rapid acceleration, excessive idling, and extra weight in the car leads to wasted gas.

An article from the California Energy Commission states “According to the U.S. Department of Energy (DOE), as a rule of thumb, you can assume that each 5 mph you drive over 60 mph is like paying an additional $0.21 per gallon for gas (at $3.00 per gallon).” That can add up, and it’s something to think about as you’re racing to get home from work each day. Is it really making a difference? If you could have all that extra money back at the expense of saving a little time, would you?

The information below, from Consumer Reports, breaks down a sampling of seven cars and what their mile-per-gallon (mpg) is at speeds of 55 mph, 65 mph, and 75 mph. The cars with the best fuel economy ironically show the largest drop in fuel economy at higher speeds.

Acura TSX 2.4-liter 4-cyl.

55 mph – 39.9 mpg
65 mph – 35.5 mpg
75 mph – 30.7 mpg

Honda Insight 1.3-liter 4-cyl.

55 mph – 51.9 mpg
65 mph – 44.8 mpg
75 mph – 36.5 mpg

Lexus RX350 3.5-liter V6

55 mph – 30.9 mpg
65 mph – 27.4 mpg
75 mph – 23.0 mpg

Mercury Mountaineer 4.6-liter V8

55 mph – 23.8 mpg
65 mph – 21.2 mpg
75 mph – 17.8 mpg

Toyota Camry 2.5-liter 4-cyl.

55 mph – 40.3 mpg
65 mph – 34.9 mpg
75 mph – 29.8 mpg

Toyota RAV4 2.5-liter 4-cyl.

55 mph – 34.6 mpg
65 mph – 29.3 mpg
75 mph – 25.9 mpg

Toyota Yaris 1.5-liter 4-cyl.

55 mph – 42.5 mpg
65 mph – 37.9 mpg
75 mph – 34.0 mpg

Worth it?

Driving faster equates to a quicker arrival time, but at what cost? Does a bigger fuel expense, more wear and tear on your car, and a possible speeding ticket equate to more sanity because you’re “making great time?” Or is it completely dependent on the situation (a commute to work versus a casual night out)?

Clearly, the law didn’t work as planned. The initial resistance, coupled with the law’s ultimate demise in 1995, shows that states want to have control of these laws internally. With so many disputes as to the effectiveness of laws like these, the chance of it recurring anytime soon is unlikely.

I do my best to be safe on the roads and have settled down as I’ve gotten older, got married, and become a father. The risks involved with being the menace I used to be aren’t worth it anymore. I’m not perfect and still tend to make mistakes, as most people do. When you add in the skyrocketing cost of gas, it makes sense to take my time and be safe. I also have the added benefit of saving a little cash while I’m at it.

Driving the speed limit makes sense for most people. Though, some people can’t control themselves. Can you?

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