Braking system for vehicles in particular commercial vehicles

The braking system has a braking source, e.g. a foot brake valve (1), providing a required braking signal and separate brake pressure reservoirs (2-4) for normal supply of the rear brake cylinders (13,14) and the front brake cylinders (31,37) and emergency supply of the front brake cylinders. The front brake cylinders have pressure regulating modules (29,35) controlled electrically by the braking signal provided by the braking source, with a switching valve (33) allowing at least one of the pressure regulating modules to be supplied from the emergency brake pressure supply reservoir in a test or emergency mode.