MPG under the microscope

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Updated Mar 20, 2020

High fuel prices call for more sophisticated analysis of usage.

In the fall of 2006, after analyzing all driver-controlled variables affecting miles per gallon of fuel, Pitt Ohio Express launched a driver training program. The Pittsburgh-based company expects that over time, the “SSI” program – which focuses on improving driver habits for shifting, speeding and idling – will save millions in fuel costs.

“The driver knows that if he controls SSI, he does not have to worry so much about mpg,” says Kent Szalla, director of business systems for Pitt Ohio Express. The company has tracked mpg improvement at all terminals that service its next-day transportation network for the Mid-Atlantic region, Ohio and West Virginia, and the Detroit and Chicago metropolitan areas.

As fuel prices rise, Pitt Ohio Express digs deeper. Recently, Szalla employed a statistical tool called regression analysis to determine the significance of non-driver variables that impact mpg. The original set contained 11 variables, which included the age, make and location of vehicles.

Still, something didn’t quite make sense. When looking at the variation in the average mpg for each terminal, Szalla saw that Chicago consistently scored better than Pittsburgh despite the fact that there was virtually no difference in any of the variables. At first, management attributed the variation to a new terminal manager and to better driver attitudes in Chicago, Szalla says.

These assumptions proved false; the truth emerged when analysts factored in weight. Pittsburgh shipments are, on average, about 500 pounds heavier than those in Chicago, Szalla says. So the heavier operation burned more fuel. Szalla also found that weather caused a variation in mpg: This problem was corrected by using a formula to “normalize” the variation due to weather in order to compare mpg performance among terminals more objectively.

With no relief in sight from high fuel prices, data-savvy fleets like Pitt Ohio Express are analyzing fuel efficiency from all angles. At $5 per gallon, any strategy that leads to even the smallest improvements in fuel efficiency could save many thousands of dollars in fuel costs. Information technology is an essential weapon in this battle, giving fleet managers the visibility and control needed to conserve fuel.

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Drilling down mpg
Since the electronic engine became standard in the 1990s, fleets have had access to vehicle and driver performance data via the vehicle’s electronic control module (ECM), which broadcasts data through the J1708 and J1939 vehicle networks. For years, fleets were able to download this data with a physical link that could be done only when the truck was in the shop bay. Today, however, many fleets use mobile onboard computers with high-speed wireless connections for continuous visibility of driver and vehicle performance.

Pitt Ohio Express has instant access to driver and vehicle performance data through an application called PerformX from PeopleNet, the company’s onboard computing and communications provider. Pitt Ohio Express uses PerformX to continuously monitor each driver and terminal relative to the company’s SSI goals, Szalla says.

A useful approach for analyzing ECM data is a daily or weekly driver scorecard to highlight all driver-controllable behaviors that impact fuel consumption. Onboard computing provider DriverTech has a “driver daily rollup” that customers can use to monitor and coach drivers, says Bill Bland, the company’s vice president of business development.

DriverTech’s DT4000 TruckPC uses an embedded Windows XP operating system with a tri-mode (satellite, cellular and Wi-Fi) communications modem. Increasingly, DriverTech customers are setting up exception alerts that allow them to identify and correct driver behavior and performance. For example, if the driver travels out of route, a driver manager could catch it immediately and respond as appropriate, Bland says.

In addition to using scorecards and real-time monitoring tools, technology providers offer analytical and business intelligence tools to help fleet managers better understand and manage fuel efficiency metrics.

“Mpg itself is an overall average that is not very useful,” says Tom Flies, senior vice president of product management for Xata Corp. Xatanet, a Web-based software application for Xata’s onboard computing platform, provides different categories for viewing fuel consumption, including the number of gallons consumed by route, by speed range, by weight (i.e. ton-miles per gallon), or when cruise control is either on or off.

Managers also can use Xatanet to establish standards for each category with historical averages, allowing them to evaluate a driver or vehicle by comparing individual performance against the standard for a peer group, such as drivers that travel the same route. Xatanet also includes a data warehouse software application called Business Objects to import data from multiple sources for analysis to create “what-if” scenarios, Flies says.

Qualcomm currently offers a performance reporting application in its OmniVision suite of products to report fleet and driver performance for idling, speed, mpg, etc. This fall, the company plans to release a new Web-based software model called OmniVision Analytics, says Norm Ellis, vice president and general manager of transportation and logistics for Qualcomm Enterprise Solutions. Fleets will be able to use the new tool to analyze fuel efficiency in many ways, such as to determine the impact of weight on mpg or to compare the fuel efficiency of different makes, models and equipment specs, Ellis says. And by importing information from other sources, a fleet could, for example, compare revenue collected from the fuel surcharge in a certain lane versus the actual cost of fuel consumed.

Tracking fuel use directly
The vehicle’s ECM contains the most detailed source of information for fuel efficiency, but it is not the most accurate method. The ECM calculates fuel consumption based on formulas and operating data from the engine – not the actual amount of fuel injected into the cylinders.

The most accurate mpg data still comes from using the actual gallons purchased and mileage. The difference between the mpg as reported by the ECM and fuel purchase data may be small, but it’s important to watch, says Greg Walsh, director of maintenance for New World Van Lines, a 250-truck household moving company based in Chicago.

Walsh monitors mpg from the ECM and from fuel-card transactions. At any time, the two mpg readings could vary by as much as a truck’s maximum tank capacity, he says; for example, a mpg calculation could be off by 300 gallons until the driver fills up at the next location.

Comparing the two sources of mpg side-by-side is necessary to isolate the cause of a sudden dip in mpg, Walsh says. At $5 per gallon, fuel theft is always a possibility. “It doesn’t take much to walk away with 100 bucks,” he says. To deter theft, fleets can set parameters – location, dollar and gallon limits and distance, for example – for drivers’ use of fuel cards.

Measuring results
Regardless of what information technology most fleets use to monitor and control fuel consumption, most fuel conservation efforts center on changing driver behavior. Technology provides the essential link for determining if driver training and other fuel strategies really are working.

A private fleet for Poland Spring, a division of Nestle Waters, transports spring water to bottling facilities in the Northeast. The company always is testing different fuel-saving strategies, such as biodiesel, aerodynamics, synthetic oil and tire pressure monitoring, says Chris McKenna, Northeast inside fleet manager. McKenna tests any new strategy by using a couple of trucks at a time.

Using a reservoir of data collected by the fleet’s Cadec Mobius onboard computers, Poland Spring is able to benchmark any fuel-savings initiative, particularly when drivers change behaviors. “Without a backup (of data), you don’t know how well you can control (mpg),” McKenna says.

Two strategies that have had the biggest impact are posting a list in the office that ranks drivers by fuel efficiency; and a weekly individual performance review with each driver. This year, the company has reduced idle time by 41 percent and is on track to save more than $21,000 in fuel. “We see (the savings) in our fuel bill and give an incentive bonus to drivers,” McKenna says. “Everybody can see that.” The company also is targeting to raise its average mpg to 6.5 this year, he says.

Many different technologies can be used to closely monitor and analyze fuel consumption and costs. No matter what technology you use now or in the future, the rising cost of fuel demands a new level of expertise in using these methods to maximize fuel savings.

MPG with a guarantee
PeopleNet backs up consulting fees for fuel savings

In April, PeopleNet announced a new consulting service for all areas of a fleet’s fuel spend. The program is called the MPG Guarantee because if the actual fuel savings in the first year do not exceed the cost of the consulting service, PeopleNet will refund the cost of the program. The goal is to improve fuel performance between 5 and 10 percent, says Louis McAnally, director of professional services.

The program begins with an on-site analysis and consultation that lasts between two to three weeks. The on-site consultant assembles a team of executive, maintenance, finance and operations people to gather information and formulate strategies to improve driver habits, agreements with fuel providers, maintenance processes, dispatch and operational efficiency, equipment specifications and more.

“You have to look at all areas,” McAnally says. The consultant uses a “very sophisticated” master template that holds up to three years’ worth of data in a spreadsheet application to track progress and show what the fleet would have spent if they had not made any changes. Fleets get to keep the master template.

After the initial consultation, the consultant holds weekly conference calls. The program concludes with an on-site visit for a week to make sure all the tools are in place and to build a long-term strategic roadmap.

Maintaining MPG
High fuel prices add new mission for maintenance software

Fuel consumption always has been an element in maintenance programs, but the escalation in prices means that improving fuel economy now is on a par with maximizing vehicle uptime and minimizing costs as shop priorities. These priorities sometimes are in conflict, so fleet managers must make more complicated decisions than ever. These judgments often require savvy analysis. Some of the more sophisticated and advanced maintenance software packages can track and analyze fuel economy by driver, vehicle, engine specification and many other categories in order to take immediate steps to improve it.

Arsenault Associates, provider of Dossier fleet maintenance software, recently announced it has realigned its development priorities to concentrate on reducing fleet fuel consumption. The company will focus on the three items with the greatest influence on fuel economy: drivers, tire pressure and vehicle operations. Charles Arsenault, chief executive officer, says his company’s target is to increase its customers’ mpg by a minimum of 0.5 mpg, with an overall fuel cost reduction goal of 10 percent.

The plan is for Dossier to provide automated operational efficiency comparisons that will rank drivers by efficiencies and variations to equipment norms. This ranking feature will help fleet managers easily identify problem drivers and quickly raise the fleet’s mpg mean average, Arsenault says. These enhancements will be made quickly and are expected to be delivered to Dossier users by October.

TMT Fleet Maintenance has multiple ways to analyze the fuel efficiency of vehicles and drivers, says Scott Vanselous, senior vice president and general manager of TMW Asset Maintenance, a division of TMW Systems. To calculate mpg by vehicle and by driver, the software automatically brings in vehicle mileage data by interfacing with a fleet’s mobile computing and communications system. The software also brings in the actual gallons from fuel cards. With a few keystrokes, fleet managers can report fuel economy by any combination of categories – equipment location, driver, engine make, truck manufacturer and model year, among other variables.

Instant alerts can be set up to identify when a vehicle falls out of normal operating range during a fuel cycle. Fleets can create their own maintenance metrics and use a real-time performance monitoring tool called ResultsNow from TMW Systems to display the results. TMW Systems also has an alert tool called the Dawg that facilitates instant e-mail alerts to managers if an individual vehicle falls outside acceptable parameters.

What’s your real MPG?
To calculate fuel economy, you simply divide the number of miles traveled by the number of gallons burned, right? Yes and no.

True, this straightforward formula gives you total miles per gallon, but it doesn’t tell the whole story. Arguably, you would paint a more meaningful picture of your fuel economy by discounting miles operated and fuel burned without producing either revenue or a surcharge. Consider the following sample scenario:

Basic calculation:

ABC Trucking’s trucks average 500 miles a day, burning 80 gallons of diesel. The nominal average fuel economy, therefore, is 6.25 mpg.

Adjusting for wasted miles:

On average, 7 percent of ABC Trucking’s total miles are empty and 5 percent are out of route. Therefore, the carrier’s trucks average 440 revenue miles a day while burning 80 gallons of diesel. Adjusted fuel economy, therefore, is 5.5 mpg.

Adjusting for practical versus HHG miles:

ABC Trucking’s customers pay based on household goods miles, and the difference between HHG miles and practical miles is 3 percent. Factoring in this difference in addition to empty and out-of-route miles means ABC Trucking’s trucks average about 427 revenue miles, still burning 80 gallons. This further adjustment produces an effective fuel economy of 5.34 mpg.

Adjusting for idling (if necessary):

ABC Trucking probably tracks fuel economy over a period of days or weeks, so it would account for any fuel wasted by overnight idling. Suppose, however, that the carrier tracks fuel economy only on a daily basis and that the 500 miles/80 gallons represented a single driving shift. In that case, ABC Trucking should discount fuel economy further. Assume the driver idles the truck for 8 hours, burning 8 gallons of fuel. Now, you have 427 effective miles, burning 88 gallons, for a fuel economy of 4.85 mpg.