Developed by Siemens VDO automotive. This is a brake by wire system working on 12 volt electrical system, which is expected to provide increased safety and comfort relative to the hydraulic brakes.

EWB has an intelligent wheel braking module on each wheel. The module consists of the following :-

1. Brake discs, which absorbs the kinetic energy.

2. Brake calipers on either side of the brake discs.

3. Brake pads. There is a stationary brake pad on one side and a moving brake pad on the other side of the brake discs.

4.  Electric motor, which controls the position of the moving brake pad, through wedge mechanism.

5.  Wedge bearing mechanism, providing connection between the brake caliper and the moving brake pad. It's special geometric shape provides the self energising effect of the brake.

6.  Sensor system for monitoring the movement and force. These measures the current wheel speed about one hundred times per second and braking force and wedge position very accurately. Thus no separate ABS is required.

When the driver presses the brake pedal to apply brakes, the EWB system sends the signal electronically to all the brake modules. On receipt of this activation signals, electric motor actuates wedge bearing mechanism to move the wedge into the required position as per the sensor feedback. This causes the moving brake pads to be pressed against their brake disc. A very rapid braking effect results due to self energisation effect of the wedge. The possibility of wedge blocking is avoided by the electronic control.

Various advantages of EWB are :-

1.  Simple construction, decreased overall weight and greater reliability due to elimination of components such as brake cylinder, brake booster, anti lock braking system units, piping, etc.

2.  This system is effective not only for the application of brakes while the vehicle is moving, but is also used as automatic parking brake, doing away with the hand brake. For this only a parking switch is required which simply activates all the four EWB modules.

3.  No brake pedal pulsation due to ABS functioning, since there is no need to have separate ABS in this system and there is no physical connection of the braking module to the brake pedal, the entire system being purely electronic.

4.  Can be adapted to newer vehicles more easily and faster, thus reducing development costs.

The only doubt about this brakes is about their reliability. Since the entire system basically depends on the battery supplying 12 volts and the vagaries of a computer, it would not be cent per cent fool proof unless some back up system is provided in case of failure of the main system, but Siemens are not explicit on this.