Investigation of vehicle and driver aggressivity and relation to fuel economy testing

As vehicle technologies continue to improve it is becoming more evident one of the last major factors impacting fuel economy left today is the driver. In this study the driver is defined as the operator of a vehicle and the difference between driving styles of the driver and vehicle is defined as aggressivity. Driver aggressivity is proven to have a substantial impact on fuel economy in many studies. Many fuel economy tests have been created, all to measure the fuel efficiency of today's vehicles and their related technologies. These tests typically require that the drivers be trained or experienced in fuel economy testing unless the impact of the driver on fuel economy is the variable being tested. It is also recommended, for certain tests, that the driver stay with the same vehicle for the tests entirety. Although these are the requirements, having the same trained drivers for the entirety of a fuel economy test may not always be a viable option. This leads to the question of, what impact can a set of drivers, who are asked to drive the same, have on fuel consumption during a fuel consumption test? The SAE J1321 Type II Fuel Consumption Test Procedure was followed on two identical trucks with two drivers that were untrained in fuel economy testing in order to answer this question. It was found in this particular study that the driver variability can impose up to a 10% fuel economy difference on shorter distance routes where the driver is kept the same. By increasing the distance of the route and swapping drivers variability in fuel economy reduced to 5%. It was shown by this particular test that the impact of the driver when asked to drive the same is minimal compared to real world results of up to 30%. A larger data set and more testing is still necessary to completely understand and validate the impact of the driver on fuel economy testing.