The safety of vehicles on roadways depends, among other things, on a properly operating brake system. Commercial vehicles such as trucks and buses are equipped with an air brake system that uses compressed air as the energy-transmitting medium. The brake response time is a critical parameter that affects the stopping distance of a vehicle. The existing air brake system in a commercial vehicle has mechanically operated valves and pneumatic hoses that are used to transfer the compressed air from the storage reservoir to the foundation brake. Replacing the mechanical valves with electronically operated regulators and reducing the pneumatic lines will potentially reduce the brake response time thereby providing a reduced stopping distance. This study focuses on the development and mathematical modelling of an electropneumatic brake system for commercial vehicles. A mathematical model that correlates the pressure transients in the brake chamber to the voltage input provided to the electropneumatic brake has been developed. The efficacy of this model is tested by comparing its results with experimental data for various test runs. This mathematical model will be used towards model-based control and fault diagnosis of the electropneumatic brake.