THE 3 Series uses four-wheel ventilated disc brakes as standard - 286mm diameter front and 280mm rear - with traction control (ASC+T), anti-lock braking (ABS) and cornering brake control (CBC) systems also standard. ASC+T, or Automatic Stability Control + Traction, prevents wheelspin by cutting engine power to the rear driving wheels. Linked to the four-channel ABS system, CBC regulates rear-wheel brakes to prevent oversteer and maintain stability when brakes are applied mid-corner, particularly at high speed. BMW's Dynamic Stability Control (DSC), which uses a yaw sensor and is able to brake all four wheels individually, is optional.