A study at the University of Sydney's Motor Vehicle Testing Lab is using exhaust sampling and data processing to create maps of fuel consumption and emissions based on vehicle speed and acceleration. These maps help understand how design affects fuel economy, predict fuel use in real traffic, and develop a model for fuel consumption. Tests show that vehicle maps are a useful tool, revealing the impact of factors like vehicle weight and faulty emission controls. The study also predicts fuel use and emissions in Sydney traffic and estimates the effects of changing speed limits. The data collected is shaping a fuel consumption model in progress.