Commentary: Fuel Economy is Two-Dimensional

February 2015, - Editorial

by Rolf Lockwood

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Rolf Lockwood, Executive Contributing Editor
Rolf Lockwood, Executive Contributing Editor

Fuel economy, fuel economy, fuel economy. Sometimes it seems to be the only topic in the air, dominating conversations among truck operators and presentations made by manufacturers and suppliers. Not to mention an enormous stack of articles written by people like me.

I wonder, though, if we actually look at it in the right way. Are we too one-dimensional? I think so, and I have the feeling that it could hold you back when you’re looking for efficiency in your fleet.

The thing is, fuel economy is really a two-sided matter. I mean, we should be striving to avoid zero mpg just as much as we aim for 10 mpg.

This wildly profound thought (tongue in cheek here) came to me as I was preparing for a panel session at a symposium staged by the leasing/rental folks at Ryder Canada late last year. In front of a few dozen of its customers, we examined the quest for fuel economy from several angles. My subject was how to manage the hardware, from spec’ing to maintaining and on to operating it. Fellow panelists were a veteran driver/driver trainer and a prominent proponent of the natural gas option.

There wasn’t enough time to get too deeply into any single aspect of the fuel economy adventure, so I had to be succinct in my comments. I spent a couple of days trying to distill my thoughts, looking through my very big directory of files on the subject, thinking hard.

And then I came upon the notion that we don’t see the whole picture. We want to get 8 mpg instead of 6.5, so we explore the options from lightweighting to aerodynamics. We look at tires and lubes and all manner of such things, every one of them aimed at using the least amount of diesel. And we use up a zillion hours in the process of finding the right hardware to achieve that goal.

With less rigor, less precision, and usually a much softer focus, we also look at how the maintenance shop operates. There, our aim is to get the truck in and out again lickety-split. It’s about time, and time only.

Likewise, our approach to the operations side is also about time, and of course productivity. Gotta keep those trailers moving, must get the most out of drivers before their hours are up.

Time, time, time.

But really, the maintenance shop and the dispatch desk are all about fuel economy. Specifically, they’re about avoiding zero-mpg moments. When that truck is broken down on the side of the road because maintenance hadn’t been done well enough, it’s getting no miles per gallon.

When the paperwork wasn’t managed well and the truck is sitting in secondary at the border while a bunch of phone calls and faxes are whizzing about, it’s getting zero mpg.
When the truck is sitting still in a rush-hour traffic jam because the route and schedule weren’t carefully planned, the fuel tank is being depleted with no work being done.

There’s the second dimension of fuel economy, and I think those unproductive stretches have to be computed in your miles-per-gallon assessments. If a given truck is achieving 10 mpg when it’s running, that’s great. But now calculate how often it’s getting zero mpg and subtract. There’s your real-world, actual fuel economy.

Just something to think about.

Rolf Lockwood is vice president, editorial, at Newcom Business Media, which publishes Today’s Trucking. He writes for HDT each month on the making, maintaining and using of trucks. He can be reached at [email protected] or 416-315-1829.


  1. 1. Big yellower [ February 23, 2015 @ 03:12AM ]

    All these crazy trailer skirts, and plastics tub objects really don't do much for MPG. They cause side drag. Increase the chance of a rollover over 75% In wind . Back in 2009 there was study down it's all based on what the power unit ( road tractor) is designed.
    Example a freightliner cl120 Columbia condo with full fairings. 5% for vertical full fairings,
    and 5% for horizontal full fairings .. I used to get 10 mpg pulling a regular 53' van ..
    The key is having the trailer up against the tractor and trailer axles about 3' to all the way back to rear bumper.. Both tractor and trailer will ride perfectly balanced which does reduces drag. Also upgrading to new parts
    and aftermarket parts can gets gains up to
    4 mpg.on power unit . It all comes down to the power unit design.
    Also road tractors that open all the way up
    (HP) and speed to at least 80mph will Burn less fuel at higher speeds . I can run from
    SLC UT to Commmece city CO on I-80 at
    70-75 mph and use only a quarter tank of fuel. About 70 gallons . Note I have fuel 150
    Gallon tanks . Having power units with less than 140-150 gallon tanks is not practical ..
    Most new rigs only have 90-120 gallon fuel tanks . Range is reduced a lot..
    My range is around 1600-1800.miles max 2000 miles under decent weather and road conditions.
    Smaller tanks maybe a 800-1100 miles. 1200 max on duel 120. You been running close to bone dry.
    You do the math.. Having a 8,000 lbs trailer is nice if all the carriers could afford them. Not just the huge carriers that dominate .


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