The motor vehicle emissions testing laboratory at the university of Sydney was commissioned this year and this report reviews the experimental data obtained to date. Preliminary experiments have investigated the steady state emission and fuel consumption behaviour of our research vehicle and determined correlations between emissions and fuel consumption and vehicle mass. Sixty four ADR 27a tests have been completed and emission and fuel consumption maps for these experiments are presented. These maps have been obtained from four different vehicles and show the effects of changes in vehicle design and emission control system and state of tune faults. It has been found that emission and fuel consumption maps from different vehicles reflect the differences in design of these vehicles whilst maps from similar cars are similar. Maps from cars with faults show features which enable the fault to be identified and the features relating to each fault are consistently reproduced regardless of vehicle design. The variability, or deterioration, of emission control devices has been investigated and an instance of egr deterioration was found in a low mileage gemini. The data and mapping techniques presented here can be used as an aid in the development of regional emission control strategies and traffic management decisions (a).