How Cruise Control Saved me Money and Made me a Better Driver

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2014 Focus SE. Estimated MPG 27 City 37 Highway. How will our test subject do?

“You’re driving like my grandpa” my fiancé says while another car blows us away on the freeway.  “What’s the point of all this again?” I look down at the MPG tracker on my cars dashboard and see I’m getting a combined 35MPG (Well above the 32 Combined MPG advertised) and I’ve only been doing this less than a week.  “I’m getting great gas mileage!” Is all I say trying to ignore the fierce glower coming from the passenger seat.  But what is the secret to this “amazing” gas mileage?  Is it new fuel, tires, or oil?  The answer is probably something you probably don’t utilize enough (or at all) on your car: The cruise control button.

I used my cruise control for a week to see what kind of mileage I could get.  My average (combined) gas mileage was hovering around the 30-32 range depending on how much city and highway drivin
g I was doing.  Generally I have a mixed commute of about 25 miles (round trip) with a balance of city and highway driving (about equal).  The goal was to see just how much this would affect my gas mileage.   As anyone with bills to pay knows, saving gas = saving money.
Going into the “experiment” I didn’t expect a whole lot of difference.  I felt I did a good job of maintaining my speed, accelerating, and staying within a reasonable number of the speed limit (usually no more than 5 over).
The vehicle I used was a 2014 Ford Focus, a vehicle known for its great gas mileage.  I was a bit skeptical, and did not think anything would change, but I decided to put my Focus to the test all the same.

The “experiment” was this: to use cruise control as much as possible and to see just how it affected my gas mileage at the end of a week.  I would set the cruise control to the speed limit, and no more than 5 above it, using cruise control as necessary to raise and lower speed.  Without any further delays, here is what happened.

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Cruise control from an old body style Ford Escape

On the first day of the experiment I learned some very basic things about cruise control I never realized.  The first thing I realized is that you have to be going over at least 20 miles an hour to engage cruise control.  This sort of put a damper on the “use cruise control as much as possible” thing.  I quickly realized I’d have to accelerate to 20MPH to engage it.  I turned off onto a 45 MPH road accelerated to 20 then engaged my cruise control.  What I immediately noticed is that the acceleration from 20-45 seemed like an eternity.  Wow this cruise control is slow, is something wrong?  I turned onto a busier highway and turned into traffic and engaged cruise control at 55MPH.  Cars whizzed by me as I made the climb to 55.  I immediately thought this cruise control thing just wasn’t for me, especially when I made the climb from 20 to 70 onto a freeway from a very small on ramp.

My next hurdle came when I got off the freeway and into my city driving stint.  I found I had to go from 45-35.  I decreased the speed, and noticed the car in front of me was getting closer, and closer, and finally had to hit the brakes to slow the car then re-engage at 35.  “Wow this cruise control can’t brake correctly either!” I thought.  This experience lasted the rest of the day unfortunately, but despite almost being run off the road, near rear ends, and brake slamming my gas mileage had improved significantly.

As the days wound on, I noticed something that I had never realized before; I had several very bad and potentially reckless driving habits.  I began to get used to gradually accelerating (even without cruise control), beginning to look further ahead and starting to brake or letting the car coast to a stop further back, and (most importantly) maintaining a constant speed and not exceeding the speed limit.  One (good) side effect was that I had developed safer and more consistent driving habits.  I came to the realization that it wasn’t necessarily the cruise control that was saving the gas mileage, but the good driving habits it was “forcing” on to me.

Naturally the ability to maintain a constant speed (especially on long freeway drives) is going to save some gas, but the ability of cruise control to “train” me to be a better driver was highly unexpected.  The good news is that after doing some research, people who’ve conducted this same “experiment” much more scientifically and with better measurements, agree with my conclusion.

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38.4 MPG. Not too bad!

At the end of the week my MPG had increased between 6-7 MPG more than my average with the same amount of driving.  I filled up and I had 445 Miles to Empty (with a 12 gallon tank my censor said 38.4MPG).  There are several reasons for this increase:

  1. Driving the Speed Limit

The government’s official website fueleconomy.gov points to research that every 5 MPH you drive over 50 MPH is like spending another .16 cents per gallon on gas (paying $2.33 a gallon).  The higher your speed, the more you pay.  So while not necessarily a direct effect of cruise control, it was a significant source of the increased gas mileage.  An added bonus is by not speeding you won’t be given a costly speeding ticket!

  1. Moderate Acceleration
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Chart showing the correlation between speed and fuel economy

A recent study by Edmunds.com found that taking an extra 5 seconds longer to accelerate from 0-60 can increase your fuel economy by up to 37%.  It is also easier on your engine, and can prolong the life of your vehicle considerably.

  1. Easing on the Brakes

I found that by not slamming on the brakes, and “coasting” when I saw a red light in the distance, would often mean that my car would still be in motion when the light turned green, meaning I was not starting again from a dead stop.  Scientifically speaking this means you are never acting against your cars forward momentum, and if you factor in how much energy it takes to take a thousand pound (or more) vehicle from a dead stop to full speed.  Substitute energy for gas mileage and you get the point.

  1. Maintaining a Constant Speed

In the Edmunds article previously cited, maintaining a constant speed increased gas mileage from 7-14%.  This test was done at 70MPH so imagine if that speed you were maintaining was 50MPH and the savings could be potentially even greater!

The conclusion is that yes cruise control can and will save you gas, but it will also make you a better driver.  Cruise control should only be used on highways or areas with low amounts of traffic for the driver’s safety.  Before engaging cruise control, be sure to read your owner’s manual so you know how to properly engage and disengage the cruise control in your vehicle.

Personally I can live with being called “grandpa” if it means I can continue to get the amazing gas mileage I’ve been getting.  Time to start stuffing all that extra dough under the mattress just like grandpa always showed me!

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