The article presents a study on Australian light duty vehicles, where fuel consumption and emissions were tested on a dynamometer. Maps were created to show how fuel consumption and emissions change with vehicle speed and acceleration. A power demand model was developed to predict fuel usage and emissions for different driving conditions. The model accurately estimates fuel consumption for trips over 10 km and within 2% accuracy. For shorter trips, the estimates are within 9% accuracy. A correction matrix was also created to adjust the model for vehicle inefficiencies at low speeds.