Go 55 to save on gas - if you have nerves of steel

By Peter DeMarco
Globe Staff / October 30, 2011

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No way. Never again. Not if you paid me.

To squeeze the most miles out of a gallon of gasoline, the federal government says, we should all be driving 55 miles per hour on the highway. So I tried doing just that, spending an entire hour on the Massachusetts Turnpike with my cruise control set at 55. Let me tell you, it was one harrowing ride.

Big-rig truckers nearly ran me off the road. Tailgaters scowled angrily when forced to go around me. One guy, driving a Ryder moving van, honked at me to get out of the way - and I was in the slow lane.

It got so bad I had to put on my hazard lights to feel safe.

The flow of traffic on the Mass. Pike, even outside of rush-hour times, is that fast.

“Can you believe the anxiety at traveling at 55?’’ asked my dad, Sam, who had signed on as my copilot. “Adding up all the emotion, is it worth the dollar value of gas you save? Can you actually drive 55 on any major highway like this?’’

I was motivated to drive 55 out of disappointment with my new car’s mileage. Everything I had read about the 2011 Chevy Equinox said it would get an estimated 29 miles per gallon on the highway. But after months of driving, I was lucky to break 24.

In July, I wrote a column about how the government determines fuel economy figures, learning that the highway estimate is, in some ways, a best-case scenario. Experts from the Environmental Protection Agency and the car-advice website told me lots of things have to go right to achieve that figure: You need a flat road, it can’t be too hot outside, you can’t get stuck in traffic.

Your driving methods also play a large role. To get the advertised mileage, you want to minimize braking and accelerating, so it’s best to use the cruise control. Also, overinflate your tires by 4 psi; don’t use your air conditioner, which taxes the engine; stay in top gear; and avoid weaving in and out of traffic. In short, even if you aren’t a Prius-owning hypermiler, you should be driving like one, the experts said.

“If I were you, what I’d like to know is, what is my vehicle capable of getting for mileage [under] absolutely perfect conditions, and how close can I replicate that in your normal driving,’’ said Phil Reed, senior consumer advice editor at

“I would find a nice flat section, probably on the Mass. Pike,’’ he continued. “Set the cruise control and reduce the air conditioning as much as possible and let that be your benchmark. And hopefully, that number will be 29 m.p.g. or more.’’

It’s 60.5 miles between the Mass. Pike’s Weston tolls and Exit 8 in Palmer, which seemed like a reasonable distance for a fuel economy experiment. Reed, a veteran mileage evaluator, warned me that driving 55 would be no joyride, but I wanted to put the government’s recommendation to the test. For a comparison, I set the cruise control at 65, the Mass. Pike’s official speed limit, for the return trip.

My dad and I reached the highway just before 10 a.m. on an overcast Thursday. After the toll booth, it took about a mile to ramp up to 55 miles per hour and lock in the cruise control. From that point on, we glued our eyes to my car’s computerized fuel economy gauge, recording our miles-per-gallon figure exit by exit.

But driving 55, as I’ve stated, wasn’t so easy. Originally I assumed I’d make the entire trip in the slow lane, but truckers, who are restricted to the right-hand lanes of the highway, need that space to maintain their speed. Since truckers typically drive at 65 miles per hour, both to make good time and to have enough steam to power up hills, I was an annoying obstacle, and they let me know it.

So, to the middle lane I went. But drivers there don’t expect you to be going 55, so I was constantly tailgated and sometimes cursed.

“We should have a sign on the back that says, ‘test car’ or ‘m.p.g. test car,’ ’’ my dad quipped. “That’s the only way to stop people from pressuring us.’’

But sure enough, our average mileage figure for the trip began to climb. When we passed Exit 13 in Framingham, it was 28.5 miles per gallon. By Interstate 495, it was 30.8. A few miles later, as we cruised up and over Worcester’s hills, we topped 31.

Finally, approaching the Palmer ramp, I killed the cruise control and checked our figure for the final time: 32 on the button, a full 3 miles per gallon above what even Chevy said the car could get. Truth in advertising, after all.

The tradeoffs for getting such great mileage, of course, were numerous. As the temperature reached 80, we were getting uncomfortable without the air conditioner. What would normally be a 50-minute ride took 63 minutes; even school buses blew past us.

But the worst drawback was that we just didn’t feel safe at that speed.

“I couldn’t imagine doing this anytime close to rush hour. You couldn’t do it. You’d cause an accident,’’ I remarked.

“And we were on our own time, with no time clock to punch, nowhere to be, nothing to deliver,’’ said my dad, who drives a truck for a living. “If you were getting paid by the hour to drive, this would add an hour and a half extra on the clock to your day.’’

To get all the benefits out of driving 55, I’d have to always drive at that speed. The concentration and worry required for my hourlong road test, though, was enough for me.

The results on my return trip were better, at least. We put the air conditioner on low and set our cruise control at 65. People still passed us, but not everyone. We felt safe in the middle lane, even without a test-vehicle sign in the back window. And we got 29 miles per gallon, exactly as advertised.

Were our driving conditions ideal? Yes. Could I get that mileage during rush hour? No way. But to save some gas on a long drive, I would try 65 again.

Peter DeMarco lives in Somerville and can be reached at He also updates a Facebook page, “WhotaughtYOUtodrive?’’

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