Function Description

The BSI system can help alert the driver of other vehicles in adjacent lanes when changing lanes. BSI always operates together with BSW.
The BSI system operates above approximately 60 km/h (37 MPH).
The BSI system uses side radar installed near the rear bumper to detect other vehicles beside vehicle in an adjacent lane.
The side radar can detect vehicles on either side of vehicle within the detection zone shown as illustrated below.
This detection zone starts from the outside mirror of vehicle and extends approximately 10 ft (3.0 m) behind the rear bumper, and approximately 10 ft (3.0 m) sideways.
If the BSW/BSI indicator is illuminated while vehicle is approaching a lane marker, the BSW/BSI indicator blinks and an audible warning will sound three times. Then the system applies the brakes on one side of the vehicle for a short period of time to help return the vehicle back to the center of the lane.

Fig 1: Overview Of BSW System (Yaw Movement)
Courtesy of NISSAN NORTH AMERICA, INC.
BSI operates regardless of turn signal usage.
The brightness of BSW/BSI indicator lights is adjusted automatically depending on the brightness of the ambient light.

NOTE:

BSI is typically activated earlier than LDP when getting closer to the lane marker.
Warning and brake control will only be activated if the BSW/BSI indicator is already illuminated when vehicle approaches a lane marker.
If another vehicle comes into the detection zone after vehicle has crossed a lane marker, no warning or brake control will be activated.