Purpose

The Fuel Usage Exception Report is designed to highlight abnormal or suspicious fuel usage across the resources in your fleet.

A fuel period (the time span between two fuel fill-ups) will be flagged as an exception (or outlier) if the type of fuel used, or the fuel economy of the resource, lies outside the range of expected values.

How the report works

When the report is run, all fuel periods from the selected resources that occur within the selected date range are retrieved and analysed.

Each fuel period from each resource is then compared not only against the other fuel periods for that resource, but also against all other fuel periods from the other resources.

Using statistical analysis, individual fuel periods are then marked as 'exceptions' if they differ significantly from the rest of the periods.

This makes the report responsive to the usage profile and behavior of your fleet. We don't use any predefined values for what the expected fuel economy should be!

Report Example

Exception Examples

Exception	Example	Explanation	Possible Causes
High litres per km	Expected between 13.11 and 16.61 L/100km for this Resource, but was 18.17 L/100km for this fuel period	The fuel economy for this vehicle was significantly worse than it normally is.	The vehicle's driving conditions during this period caused a decrease in fuel economy (ie: urban environment, congestion, heavy terrain). The driver's driving behavior during this period caused a decrease in fuel economy (ie: heavy acceleration, poor gear choice). The fuel card was used for a vehicle other than the vehicle assigned to the fuel card.
High litres per engine on hours	Expected between 2.66 and 3.55 L/h for this Resource, but was 3.90 L/h for this fuel period	The engine hours economy for this vehicle was significantly higher than it normally is.	For machinery, this may indicate a decrease in performance or fuel efficiency of the plant. The fuel card was used for a vehicle other than the vehicle assigned to the fuel card.
Abnormal fuel type	98% of the fuel stops for this Resource are for Petrol, but this periods fuel stop was for Diesel	The majority of the fuel card transactions were for Petrol, but this particular transaction was for Diesel.	An employee has used the fuel card to fill a jerry-can or canister with a fuel type not used by the fuel cards assigned vehicle. The fuel card was used for a vehicle other than the vehicle assigned to the fuel card.
Low trip count	The resource went on 0 trips for this fuel period	The vehicle did not drive at all within the fuel period, despite the fuel card being used.	There is a fault with the GPS unit in the vehicle, which prevented all trips from being recorded. The fuel card was used for a vehicle other than the vehicle assigned to the fuel card.

Guidelines and tips

Remember, when your run the report, only the fuel periods for the resources you select, occurring within the date range you select, are used for analysis.

Therefore, for best results:

Each time the report is run, select only resources that drive or fuel up in a similar manner.
- Perhaps run the report initially for all the heavy trucks, then again later for the white fleet or light vehicles.
For improved accuracy of results, select the largest time period possible.
- This gives the report more data to work with, in order to determine the typical fuel usage.
Exclude resources which experience a wide variety of different usage profiles.
You may find that some fuel periods just slip past the range of expected values.
- Due to the nature of statistics, this will always be the case! Even if the analysis is tweaked to widen the range just a bit.
Use your own discretion and judgement when acting upon any exceptions found.
- A detailed breakdown of each fuel period for a Resource can be found in the Fuel Period Report.
- You may also find it useful to look at the Trip, Idle and Daily Usage Reports, in order to pin-point the causes of poor fuel economy.

The fine print

The statistical method used to identify outliers is the Inter Quartile Range (IQR), also known as the Inter Quartile Fence.

The IQR for 'Litres Per Km' and 'Litres Per Engine On Hours' is calculated for each resource, and for the collection of resources in the report as a whole.

Each fuel period is checked to determine if it lies outside the IQR for both its resource, then for the collection of resources..

If a fuel period is first detected as having a low trip count, or using a different fuel type than expected, then it will not be checked against the IQRs.

If a fuel period is outside the range for both the 'Litres Per Km' and 'Litres Per Engine On Hours' IQR, only the 'Litres Per Km' exception is shown.

How to use the Fuel Usage Exception Report