When the driver applies the brake pedal, a signal is sent to the vehicle's Electronic Control Unit (ECU), which determines the appropriate amount of braking force to assign to regenerative braking through the electric drive motor and to the hydraulic friction braking system. In many light-to-moderate braking situations, friction braking is not needed until the vehicle speed drops below 5 mph, as the vehicle slows to a final stop. When the ECU determines that friction braking is needed, the dual hydraulic master cylinder pumps brake fluid through the system. Midway between the master cylinder and the calipers is a separate motorized electronic actuator. This actuator receives an electronic signal, generated in the master cylinder module that precisely defines how the driver has applied the brakes – soft or hard, slow or fast. The actuator then directly apportions hydraulic pressure to the brake calipers at each wheel. To maximize the Insight's accident-avoidance capabilities, the system delivers an extra-strong braking response when the driver increases the pedal force.