In this paper a dynamic, modular, 1-D vehicle model architecture is presented which seeks to enhance modelling flexibility and can be rapidly adapted to new vehicle concepts, including hybrid configurations. Interdependencies between model sub-systems are minimized. Each subsystem of the vehicle model follows a standardized signal architecture allowing subsystems to be developed, tested and validated separately from the main model and easily reintegrated. Standard dynamic equations are used to calculate the rotational speed of the desired driveline component within each subsystem i.e. dynamic calculations are carried out with respect to the component of interest. Sample simulations are presented for isolated and integrated components to demonstrate flexibility. Two vehicle test cases are presented. The application to a conventional heavy-duty vehicle demonstrates the operational capabilities of the modelling methodology, while the inclusion of electrical components to form a mild-hybrid heavy-duty vehicle demonstrates the model’s potential for predicting improvements in fuel economy and performance over a specified drive cycle. Qualitative validation characteristics are presented, highlighting the ability of the model to accurately capture dynamic events and fuel consumption profiles.