Making Sense Of MPG: How To Use Telematics To Measure And Reduce Fuel Burn

Despite enjoying a drop in petrol pump prices, fleet fuel costs remain a top priority for businesses. But the difficulties posed by the complexity of 'what to measure' and 'how to measure' means that fleet managers and fleet business owners are often frustrated in their attempts to use MPG to drive long-term, sustainable results.

This two-part blog provides much needed clarity around the relationship between telematics and MPG and the difference between fuel economy and efficiency and fuel consumption, dispelling some popular myths in the process to set out the actual reality of measuring and reducing fuel burn. It is based on the thinking of our experienced fleet telematics team, who can provide further guidance regarding any of the ideas in this blog

Part 1 - Reality Check

There is not a right or wrong way to measure MPG, but you need to measure it accurately and consistently.

The questions businesses should be asking are what is the easiest way the measure MPG??? What are the key metrics you need to measure? If you are not hitting your MPG target, do you know why?

Knowing your MPG will not help you deliver improvements against targets, but knowing which factors influence MPG will do.

Let's deal in the reality of telematics and MPG for your business. We all know that fleet management involves an abundance of data and we all know that this is not necessarily a good thing. How much time do you waste measuring the wrong things?

Of course, this is a rhetorical question. The point we are trying to make is there are so many things that can be measured, so many data points to be tracked and so many opportunities to collect data, all of which will present themselves once your vehicles are on the road, but all of which may or may not help you to make sense of MPG.

This is a data-intensive business. It all begins and ends with the data, but because there is so much data and so many measurements, it is easy to get overwhelmed or to become so focused on certain measurements that you lose sight of the big picture.?? MPG is a case in point. If you own or manage a fleet business you are going to spend a lot of time watching fuel data, running trials, noticing things and yet, maybe nothing is changing. There is lots of data, but no information. And if you turn to telematics to help you, then the situation can get worse. You find yourself measuring more things, looking at more data and your actual fuel mileage is suddenly very different from what the vehicle says it is.

Let's get one thing straight, telematics can improve MPG, but the amount of data generated takes time to process into usable information, and if you are measuring more than one thing, then the data may not be worth using at all.

Think of how many fuel data sources there are - the pump, the bunker, the fuel card, etc. and each fleet has their own methods of dealing with them, but the integrity of the data is a real problem because a) it is rarely accurate and b) it is variable from source to source. It is therefore, no surprise that telematics data differs with the other data sources used.

But in terms of data from the engine management system, the integrity of the data is not disputed. The variable is the analysis method used, and what other data may be injected into the analysis, and with what justification, to achieve the final MPG numbers that are fed back to the driver, manager, or trainer.

There are substantial savings to made using telematics to improve MPG, but beware the salesman who sells on MPG alone. All too often there is far too much emphasis placed on the MPG figures of vehicles. The best way to reduce fuel consumption is by improving driver behaviour and MPG acts as the bottom line in this area. Good MPG figures will always be achieved through improved driving style and efficient driving style will, in nearly all cases, result in improved MPG.

MPG (The flawed metric)

In order to improve vehicles' fuel efficiency, fleet managers need methods, which can accurately measure vehicles' fuel performance. Regardless whether fuel information is obtained from fuel cards or vehicles' electronic solutions such as CANbus, fuel efficiency is generally measured in MPG, even though MPG does not include all the factors necessary to its interpretation such as driving style, vehicle weight or age, weather, road conditions etc. Furthermore, other aspects of fuel efficiency, such as fuel costs, are not directly reflected by MPG, but instead by other measures such as cost-per-mile or, more to the points, gallons-per-mile.

These limitations can potentially lead to situations where a vehicle can be MPG efficient but cost-per-mile inefficient (and vice versa) making it hard for a fleet manager to understand how efficient their vehicles are. Thus, there is a need for a method, which can address these limitations and provide a better and more comparable vehicle fuel efficiency measure than with simple MPG measurement. What we really ought to be thinking about is fuel consumption, measured in gallons per mile???not the customary MPG.

Fuel economy is a well-defined measure familiar to anybody who owns or manages a fleet of vehicles; it means MPG. Fuel efficiency, on the other hand, is a looser, descriptive term referring to how efficiently a vehicle uses fuel. Both terms are important in thinking about how to manage a fleet.?? What we really ought to be thinking about is fuel consumption, measured in gallons per mile???not MPG.?? This measure tells you exactly how many gallons of fuel a vehicle is using over 500 miles, for example.?? If you are trying to reduce fuel burn, this is what you need to look at.

Thinking about MPG can confuse matters and make small improvements seem bigger than they really are.?? For commercial fleets MPG is an illusion i.e. the metric is flawed because total fuel use is important, which is why gallons-per-mile would be a better measure.?? For example, a car driver going from A to B in a vehicle that does 40 MPG and they improve the mileage to get 60 MPG, that's an improvement which sounds impressive, but in reality they are not using all that much fuel either way.?? On the other hand, if you start with a truck that does 10 MPG and improve it to 15 MPG, the difference in the overall amount of fuel consumed is much greater, a reduction of seventeen gallons over a 500 mile trip, versus just over four gallons.

The irony for the commercial fleet business is that even though the large engines powering van and trucks are as efficient as the engines of smaller cars, the weight and drag of the vehicles they're hauling around dramatically worsens their overall fuel economy. Looking at it this way, then it becomes clear that MPG alone may not be a practical way to gauge efficiency, and if you use MPG to measure the performance of your fleet and your drivers, you may be getting inaccurate information. MPG as a stand-alone metric, therefore, just does not make sense.?? Gallons-per-mile on the other hand does make sense, simply because it is more valuable to know and measure how much fuel you are going to use on your trip rather than how far you could travel on a gallon of fuel.

Click here to find out more about how Navman Wireless can help reduce your company's fuel burn.??