In recent times, the significance of advancing road transportation technologies has notably increased. This is mainly driven by the escalating need for road transportation systems that are not only safe but also environmentally sustainable. Moreover, enhancing fuel efficiency in road vehicles (i.e., automobiles) holds the potential to contribute significantly to the reduction of a country’s economic vulnerability (i.e., improved energy security), by reducing the reliance on energy imports. While research reports and scientific journals provide valuable information on automobile fuel consumption, it is essential to continually update our understanding of the factors that influence it. This document aims to review and describe the various factors, both direct and indirect, that play a role in an automotive’s overall energy efficiency and fuel consumption.