PRE-CRASH SAFETY SYSTEM (w/o Driver Monitor Camera) GENERAL


  1. OUTLINE


    1. The pre-crash safety system retracts the slack in the front seatbelts and warns the driver by sounding a buzzer and indicating a warning on the multi-information display. Then, the system sets the brake control system in the brake assist standby mode and applies the brakes when the conditions indicated below are present before a collision. This lessens the injury sustained by the driver and front passenger.

      Operating Conditions

      • When a collision with an obstacle in front of the vehicle or a collision with the vehicle ahead is determined to be high probability of collision.

      • When the brakes are suddenly applied.

      • When the front wheels lose grip in relation to the rear wheels (front wheel skid tendency).

      • When the rear wheels lose grip in relation to the front wheels (rear wheel skid tendency).

      1. The millimeter wave radar sensor assembly and driving support ECU assembly determine whether a collision with an obstacle in front of the vehicle or a collision with the vehicle ahead is unavoidable.

      2. The millimeter wave radar sensor assembly and driving support ECU assembly make this determination based on the vehicle speed relative to the speed of an oncoming vehicle or based on the speed with which an object is being approached.

      3. The skid control ECU assembly determines emergency braking and front or rear wheel skid tendency.

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  2. PRECAUTION


    1. When the millimeter wave radar sensor assembly detects an object in front under the conditions described below, the driving support ECU assembly may determine that a collision is unavoidable, and operate the pre-crash safety system. However, this is not abnormal.

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      Text in Illustration
      *a Object on road surface at corner entrance (guard rail, street light, sign, signboard) *b Opposing traffic vehicle while cornering
      *c Narrow iron bridge *d Metal object, steel plate, or bump on road surface
      *e Opposing traffic at intersection *f When vehicle ahead is approached suddenly
      *g When passing through toll gate *h Vehicle height change significantly (front of vehicle inclined either upward or downward)
      *i Metal object such as sign board in front of vehicle on uphill slope *j Metal object or steel plate in ground at base of downhill slope

      Detection may also not be possible under the following conditions:


      • When passing road signs, billboards and overpasses.

      • When passing through an intersection.

      • When driving on a bumpy road.

      • When the axis of the millimeter wave radar sensor assembly is displaced.

    2. The millimeter wave radar sensor assembly may not be able to perform detection in the following case:


      1. A collision has occurred with an object outside the detection area.

    3. The millimeter wave radar sensor assembly might not be able to detect the following objects as collision objects:

      Objects that cannot be detected Plastic items (safety cones, etc.), etc.
      Objects that cannot be detected in a stable manner People, bicycles, motorcycles, trees, animals, snow fence, etc.

    4. The following conditions make object detection difficult or impossible:


      1. When there is a sharp corner or bumpy road.

      2. When the vehicle's direction of travel is interrupted.

      3. When in poor weather (such as rain, fog, snow, sandstorms and so on).

      4. When the vehicle height changes significantly (for example, the front of the vehicle is inclined either upward or downword).

      5. When the axis of the millimeter wave radar sensor assembly is displaced.

      6. If the vehicle is sideslipping when the VSC is not activated.