In this paper a dynamic, modular, 1-D vehicle model architecture is presented that improves modelling flexibility and can be adapted rapidly to new advanced vehicle concepts, including hybrid vehicles. Interdependencies between model sub-systems are minimized, thereby improving model flexibility in the development of new vehicle concepts and architectures. Each subsystem of the vehicle model follows a standardized signal architecture, therefore subsystems can be developed, tested and validated separately from the main model and easily re-integrated. The model uses standard dynamic equations 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. First the application to a conventional heavy-duty vehicle demonstrates the operational capabilities of the modelling methodology. Secondly, electrical components are added to form a mild-hybrid heavy-duty vehicle to serve as a comparison and show the model’s potential for predicting improvements in fuel economy and performance over a specified drive cycle.