Toyota 2014 Sienna Manual page 350

2-4. Using other driving systems
The Blind Spot Monitor function
The Blind Spot Monitor function uses radar sensors to detect vehicles
that are traveling in an adjacent lane in the area that is not reflected
in the outside rear view mirror (the blind spot), and advises the driver
of the vehicles existence via the outside rear view mirror indicator.
The Blind Spot Monitor function detection areas
The areas that vehicles can be detected in are outlined below.
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The range of the detection area
extends to:
Approximately 11.5 ft. (3.5 m)
from the side of the vehicle
The first 1.6 ft. (0.5 m) from the
side of the vehicle is not in the
detection area
Approximately 9.8 ft. (3 m)
from the rear bumper
Approximately 3.3 ft. (1 m) for-
ward of the rear bumper