Updated on 11.10.14

Eight Strategies for Fuel Efficient Driving

Trent Hamm

Lessons from Following a Hypermiler

A few weeks ago, I found myself following a strangely erratic driver while rolling along on US-163 here in Iowa.

This driver was doing several very noticeable things. For starters, this person was driving several miles an hour under the speed limit, going about 57 in a 65 MPH area. Whenever we reached a dip, he would coast up to about 65 miles per hour as we went down, then slow down to about 40 miles per hour on the way up. He would return to his previous maximum speed very, very slowly. About two miles before we reached his exit, he started to very slowly decelerate until he was going about 25 MPH as he exited.

At first, I would have passed the guy but I was actually boxed in by a long line of traffic in the other lane. After a while, though, I began to realize what he was doing. He was driving for maximum fuel efficiency.

Hypermiling

A long time ago, I read an article in Mother Jones about the exploits of Wayne Gerdes, a man who strives to be “the most efficient driver in the world.” He and his efficient-driving cohorts call themselves “hypermilers” and use a bunch of different strategies to do things like squeezing 90 miles per gallon out of a Honda Accord. (I actually wrote a very brief bit about this in 2007).

Here’s what you need to know about hypermiling.

First, it’s all about trying to squeeze every bit of value out of each drop of gas. Hypermilers can get absurd average fuel efficiency over surprisingly long trips. They do this by exploiting every advantage they can from the car from the tires to the driving technique and every system in the car.

Second, many of the strategies disregard the other traffic on the road. Often, as humans, we’re tempted to drive with the flow of traffic. It’s just in our nature – if everyone else is going a certain speed, most of us roughly match that speed and the people that don’t tend to stand out, whether it’s the guy in the Ferrari going 120 MPH or the extremely careful driver going 15 MPH under the speed limit. Many hypermiling strategies ignore that natural urge to stick with the flow of traffic in a quest to maximize fuel efficiency.

Finally, many of the strategies are easily adapted for the patient but non-hypermiling driver. Most of these things can easily be done by everyone if they just choose to be a little patient on the road.

Here are eight strategies that I’ve tried out in the last several months. Each of these strategies turned out to be very easy on their own and most have become a regular part of my driving habits.

The focus, of course, is on how much each tactic has actually saved me over a few tanks of gas. Over the last few months, I’ve been keeping careful notes on fuel efficiency and driving tactics using my 2004 Honda Pilot. I started off with a baseline where I didn’t do anything efficient at all, driving as I normally did over a few tanks, then I tried each strategy for two tanks of gas to see how much efficiency I gained and how much it saved me.

So, what’s our baseline number? When driving around and consciously not using any tactics at all, my 2004 Honda Pilot averaged about 18.8 miles per gallon over three tanks. To translate that into dollars and cents, let’s assume that fuel is averaging $3.50 per gallon, so over the course of 10,000 miles – a year of moderate driving – the cost for fuel is $1,861.70.

The biggest trick? Remembering not to unconsciously use other tactics when driving. I did my best.

Strategy 1: Inflate Your Tires to the Maximum Recommended Level

In your car’s manual, you’ll find a section that indicates the ideal maximum pressure for your car tires. Most of the time, cars are driving around on the road with a level significantly below that, which hurts your car’s fuel efficiency. Why? The less pressure in your tires, the greater the portion of your tire that is actually in contact with the road as you drive. The greater the part of your tire touching the road as you drive, the more work your engine has to do. In general, it’s suggested that for each PSI that any of your tires is below the maximum recommended level, it’s costing you 1/8% of your fuel efficiency.

Hypermilers often inflate over the recommended level when participating in hypermiling “races” (where the winner is not the person who finishes first, but the person who finishes with the least fuel used), but that’s not a particularly smart tactic because it increases the risk of a blowout.

How can you do this? Keep a tire gauge in your car – it’s a cheap little device you can get for a buck or two at any automotive store. Once a month, visit a gas station with a free air pump. Pull up there, check each tire for the pressure level, and then fill up the tires, using the gauge every 30 seconds or so to check the level. Keep doing it until each tire is filled up. It’s really easy and takes perhaps five to ten minutes once a month.

How much does it save? During two tanks where I kept my tires aired up on a monthly basis, my fuel efficiency averaged 19.9 miles per gallon, an increase from 18.8. Over the course of 10,000 miles with gas at $3.50 per gallon, that change saves me $102.90. Over the course of a year, you’d probably only have to fill your tires eight times or so (since most auto maintenance shops fill them up for you as a courtesy) and if it takes me eight minutes on average each time, that’s an hour of time spread out over a year that will save $103. That’s well worth it for me.

Strategy #2: Aggressively Avoid Traffic Lights and Stop Signs

Whenever you leave your home, choose the route that minimizes the number of stop signs and traffic lights that you’ll have to hit on your way to your destination. It just requires a bit of forethought as you’re pulling out of your driveway.

Obviously, this works best on routes that you’re really familiar with and not as well on unfamiliar routes (because you often aren’t sure of alternate routes or are trusting your GPS). Still, I did some calculating and map studying and found that there were much better routes to common places I go in terms of stopping and starting. I managed to reduce the number of stops by two just on my way to the nearest major road and I also chopped off several stops at my out-of-town destinations without adding any distance to the trips that I could discern.

How much does it save? Over the course of two tanks, comparing driving routes where I didn’t worry about stop signs and stoplights at all compared to driving routes that were carefully selected for minimal stops, my fuel efficiency went up from 18.8 miles per gallon to 20.2 miles per gallon. Over the course of 10,000 miles with gas at $3.50 per gallon, that change saves me $129.03.

Now, the real question is whether or not it adds any time to my driving. My feeling is that it was pretty much a wash. Obviously, I saved a little time by avoiding stoplights, but I had to choose routes that were sometimes a bit longer to avoid them. I tried to optimize this balance and I feel like I did a good job, with the end result being that I was probably driving just a bit more distance-wise on most trips but eliminating stops along the way. In the end, I think this was a money-saving strategy that broke even on time. I now have new permanent routes to some of the places I visit and I’m pretty sure there’s no time difference but I save on fuel.

Strategy #3: Don’t Accelerate Hard After Stopping and Glide Into Stops

You’re sitting at a stoplight waiting for it to turn green. When it does, you’re very tempted to get going, so your foot really really wants to punch down on the gas pedal.

Don’t. Acceleration devours gasoline and the harder you accelerate, the more fuel your car devours. If your car has an RPM gauge, that’s a rough approximation as to how much fuel is being burnt at that very moment, and when you accelerate hard, that RPM gauge spikes.

Instead, when it’s time for you to go, accelerate gently. Sure, sometimes a car might cut in front of you if you do it, but don’t sweat it. Get up to full speed at a gentle pace.

Similarly, when it’s clear that you’re going to have to stop in the next few blocks, take your foot off the gas and glide for a while. Only use the brake if you have to because, frankly, using the brake means you wasted acceleration at some point and acceleration is very expensive in terms of fuel.

How much does it save? I spent two tanks of gas doing this as much as possible. It’s truly a tactic that is effective in towns and essentially useless on the open road, but if you drive a mix of the two (like I do), it’s still a very good technique to learn. During the tanks where I accelerated and coasted as much as I could, my fuel mileage jumped to 21.3 miles per gallon. That would save a total of $218.50 over the course of ten thousand miles.

Strategy #4: Drive At The Speed Limit – Never Speed

I’ll be the first to admit that sometimes I get a bit of a lead foot, especially on the open road where there aren’t any cars around me. I’ll often go as fast as ten miles an hour over the speed limit in an effort to save a little bit of time.

Here’s the truth, though. For every hour I’m in the car, speeding that much only saves me about five minutes at most. Speeding really doesn’t get us there much faster than going the speed limit does. Even worse, it runs the risk of generating traffic tickets.

My strategy for implementing this “no speeding” strategy was to trust my cruise control whenever I wasn’t in town and to just trust my instincts whenever I was in town. For the most part, I think this worked very well in terms of keeping my car at the speed limit.

How much does it save? I found that avoiding speeding brought my fuel efficiency up from 18.8 miles per gallon to exactly 20 miles per gallon. Over the course of 10,000 miles, that would save me $111.70 in reduced fuel. Of course, I get to my destination a bit slower this way. On the other hand, I’m also not getting any speeding tickets this way.

Strategy #5: Don’t Use the AC

The air conditioner in a car is an energy hog. While it does cool you off, it gobbles down the fuel along the way. Air conditioning can eat up 8% of the fuel usage of a car as you’re driving along, so why not just turn it off? (Comfort is the obvious answer.)

Still, I wanted to see the real-world impact of not using air conditioning, so I turned it off this summer. Yep, for a full tank, I drove around this summer in my SUV with the air off.

How much does it save? It turns out that just by turning the air off, my fuel efficiency went from 18.8 miles per gallon to 20.2 miles per gallon. Over the course of ten thousand miles, with fuel at $3.50 per gallon, that will save me $129.03.

Is it worth it? Probably not. Instead, I think the best approach is probably a hybrid of coolness and savings. Try running the AC for a while until the interior is cool, then turning it completely off until someone is uncomfortable. Even better, turn it completely off for the last fifteen minutes of any trip, as you’ll be getting out of the car anyway.

Strategy #6: Keep Windows Closed

What about just rolling down the windows to keep cool? The problem with that strategy is that it introduces drag. The wind sucking in your windows creates quite a lot of pushback against your driving, particularly at higher speeds.

I was curious as to how much of an impact the windows actually had on my driving, so I also drove for a tank’s worth of gas with the windows down. The biggest trick for me was simply remembering to roll them up every time I stopped. I kept both the front driver and front passenger windows down and enjoyed some breezy drives this summer!

How much does it save? In order to figure this out, I chose to drive with the windows open almost all of the time (I only closed them during downpours) during a tank of gas during the summer, then with my windows closed as much as possible while avoiding running the AC in either case. I wanted to know just the effect of the windows, not the AC. This meant some warm trips, but I was pretty surprised to find that my fuel efficiency was about 16.8 miles per gallon with the windows down. Compare that to the 20.2 above when the windows were up and you’ll see the difference it makes – $350.60 per every ten thousand miles when the fuel costs $3.50 per gallon in my Honda Pilot.

Strategy #7: Ride the Road Ridges

As anyone who has driven much on the open road already knows, there are some “grooves” in your lane that are a bit lower than the rest of the road. This is because of wear – most people stick to the center of their lanes and gradually wear down the typical areas where the tire would rest.

This “wearing down” increases your tire’s contact with the road. Since it’s a slight cup, a greater portion of your car tire is touching the road and, as we mentioned above, the more your tire touches the road, the less efficient your driving is.

My strategy was to try driving over closer to the white line on the open road, avoiding those worn tire “grooves” and minimizing my tire’s contact with the road.

How much does it save? This was the single most surprising result for me. It actually raised my average fuel efficiency to 20.1 miles per gallon from 18.8. I did it twice just to make sure, in fact. Again, over ten thousand miles at $3.50 per gallon, this saves $120.41.

Would I want to do this all the time? Probably not. It felt really “off” when I was driving that close to the white line and I definitely had to give the road more cognitive focus when driving over there. I wouldn’t mind doing it for relatively shorter trips and I would want to pair it with speed limit driving, but over multiple hours, I think it would feel more draining.

Strategy #8 – Minimize the Weight

I had a great deal of difficulty measuring this one because by default I try to avoid carrying much extra weight in my car. I don’t store much long term in the trunk and certainly nothing heavy.

Instead, I decided to check on the impact of fuel efficiency if I added some weight. For two tanks of gas, I added about two hundred pounds of weight to the vehicle, most of it near the rear, but some of it near the middle of the vehicle. I found – unsurprisingly – that this caused my fuel efficiency to drop a little, but not tremendously. It went from 18.8 miles per gallon to 17.9 miles per gallon.

How much does it save? In this case, having that extra two hundred pounds of weight in the car over the course of ten thousand miles would cost me $93.61. My perspective is simple – if it’s really worthwhile to have items in your car, leave them there, but get rid of the stuff that you could easily keep in your garage or in a closet.

A Final Tip That’s Hard to Measure: Keep Up with Maintenance

If there’s one single strategy I can offer for fuel efficiency beyond what’s listed here, it’s this: keep up with your car’s maintenance schedule.

Somewhere in virtually every automobile’s owner’s manual is a list of recommended maintenance, along with the mileage at which you should get that maintenance. Not only do these maintenance stops help extend the life of your car, they also help quite a bit with fuel efficiency.

Many of the most common pieces of auto maintenance, such as air filter replacement and oil replacement, actually improve your car’s fuel efficiency. The oil keeps your motor parts running as efficiently as possible, and a new air filter maximizes the efficiency of air flow around your engine, too.

This is an aspect that’s very hard for me to measure simply because I keep my car’s maintenance schedule all of the time and I wasn’t about to let it lapse for long enough to do these kinds of calculations. Just be aware that the savings is real and it goes beyond just extending the life of your car.

Final Thoughts

For my last few tanks of gas, I’ve tried hard to use all of the above tips at the same time. Over those two tanks, my fuel efficiency has gone from the initial 18.8 miles per gallon to 29 miles per gallon. Seriously. Over the course of 10,000 miles, with gas at $3.50 per gallon, that’s a savings of $654.80.

There are some drawbacks, though. Comfort was reduced, particularly on hot days. I did run the AC a few times particularly during a very warm stretch of days in late September. Also, it is a bit slower to drive this way, especially with minimizing the acceleration and deceleration and avoiding speeding, but I rarely found that it mattered more than a moment or two and I wound up noticing weird synergies such as lower traffic on alternate routes.

All in all, this experiment has changed my regular driving habits. Sure, I’ll still speed a little bit, and I was already doing some things like airing up my tires and keeping up with auto maintenance, but most of these tactics add little or no difficulty to driving and clearly improve fuel efficiency. I consider it a big win.

Loading Disqus Comments ...
Loading Facebook Comments ...

Leave a Reply

Your email address will not be published. Required fields are marked *

Simple Share Buttons
Simple Share Buttons