Studies show that cars use significantly more fuel per kilometre than suggested by official test ratings. This publication presents an analysis of the fuel efficiency gap and examines technologies available that could reduce that gap and improve fuel economy. It examines such areas as engine and transmission technologies, hybrid technologies, tyre inflation and technology, lubricants, and fuel-saving driver support devices.  Together, these technologies could improve average on-road fuel economy by 10% or more at low or modest cost.  Policies that could be used to encourage uptake of these technologies are also identified.

Executive Summary
1. Introduction
2. Literature Review of Shortfall
-Mix of Driving Environments
-Road Conditions/Topography
-Vehicle Accessories and Cargo
-Vehicle Technology - Specific Effects
3. Effect of Ambient Conditions, Vehicle Maintenance, and Driver Behaviour on Fuel Economy
-The Effect of Ambient Conditions on Fuel Economy
-The Influence of Vehicle Maintenance on Fuel Economy
-The Importance of Driver Behaviour for Fuel Economy
4. Driving Cycles and Shortfall Data
5. Technologies to Improve Fuel Economy of Gasoline Vehicles
-Engine Technologies
-Transmission Technologies
-Accessory Technologies
-Hybrid Technologies
-Tyre Technology
-Tyre Inflation
-Fuel-Efficient Lubricants
-Fuel Economy Gains from Oils
-Headlights and Daytime Running Lights
-Fuel-Saving Driver Support Devices
6. Improving the Fuel Economy of Diesel Vehicles
-The Benefits of Diesel
-New Engine Performance
-Diesel Vehicle Shortfall
-Low Ambient Temperatures
-Aggressive Driving
-Traffic Conditions
-Effects of Other Technologies
7. Technology Costs and Policies to Promote Technologies that Improve Fuel Economy
-Technology by Location Class
-Technology Payback Period and Cost per Tonne CO2 Reduction
-Policies to Promote Technology Introduction
References