Revealed: Annual MPG Report Card

Real-world fuel economy hardly growing

Evidence from our large-scale test programme of passenger cars in Europe reveals the difference between the official fuel economy figures for new cars and their real-world results is continuing to grow.

The latest examination of our data shows that the gap between the combined New European Driving Cycle figures and our real-world results has grown to 24%. This is a dramatic increase from the 16% average variance we first recorded in 2012, and shows the degree to which official figures distort the true picture of vehicle efficiency (dotted green line on graph below).

What this means is that, in real terms, the fuel economy motorists can expect from their new vehicles is hardly growing, just 2mpg over the last three years (blue line), yet the official figures show a marked improvement (red line). While it is true that vehicles went through a phase of significant efficiency improvement in the past, these new results suggest progress in this area has now stalled.
Gap graph

The bigger picture

As older cars are replaced by their owners with newer models, fuel consumption and CO2 outputs should fall.  However,  if drivers switch from larger engines to smaller vehicles this improvement tends to be counteracted. In an earlier newsletter we described how the efficiency gap is greater for smaller-engined vehicles, and particularly downsized engines in larger cars. The very smallest cars are on average 36% below their advertised MPG.

In addition, any backlash against ‘dirty diesels’  may further work against greenhouse gas reductions if consumers switch back to the higher CO2 gasoline vehicles, despite the fact that the industry narrative and public perception about diesels may be lagging reality.  We are seeing that the latest Euro 6 diesels are significantly lower in NOx and particulates as discussed in last month’s newsletter.

The overall effect of these factors is potentially to constrain the UK’s ability to meet its greenhouse gas targets, and to cost the consumer more at the pump.

More on this…

EA has launched a new service for tracking and benchmarking MPG performance. It provides access to our database from high-level trends to detailed results from individual tests. Find out more.

The data we collect is used to populate What Car’s True MPG consumer website. For more information on which vehicles perform best and worst visit  their site.