The objectives of this project were to evaluate the reduction in fuel consumption and greenhouse gas (GHG) emissions made possible by hybrid technology, and to identify good driving habits with this type of vehicle. Two diesel-electric hybrid pick-up and delivery trucks and one diesel-electric hybrid utility vehicle equipped with an electric driven PTO (power take-off) system were included in the project.The first phase was the evaluation in actual operating conditions. Onboard computers were installed in the vehicles to record parameters that make it possible to determine driving habits. Based on operational data, specific duty cycles were built and track tests were conducted to measure the fuel consumption on these duty cycles. It was therefore possible to compare the hybrid trucks with other diesel trucks featuring similar characteristics.The delivery hybrid trucks showed up to 34% fuel savings during the track tests. Achieving major savings will require driving mainly on urban hauling routes, in a not too aggressive manner, to allow the recharge of batteries and electric-assisted power. An appropriate training of drivers is recommended and a best driving practices manual was prepared to that end.For the utility truck, the savings are greater when the PTO time is longer. Compared with the conventional control diesel vehicle, track tests showed 11% fuel improvement for a duty cycle composed of 67% driving time and 33% PTO time, and 19% fuel improvement for the duty cycle with 50% driving time and 50% PTO time.The project confirmed the potential of this technology to reduce fuel consumption and GHG emissions, even though it was generally slightly below the 30% savings reported by hybrid truck manufacturers. The GHG reduction for these trucks was evaluated at between 2 to 5.4 tonnes, based on an annual distance in kilometres of 17,620 km, which corresponds to the average annual distance travelled by a medium-duty truck in the Province of Quebec (Canada).