Ford Taurus 2011 Owner's Manual page 270

Driving
CTA coverage also decreases when parking at shallow angles (refer to
figure for approximate zone coverage areas [sensor obstructed for
vehicle on left]).
CTA detection limitations: Due to the nature of radar technology,
there may be certain instances where vehicles entering and exiting the
blind spot zones may not be detected. Below is a list of circumstances
that may cause non-detection:
• Debris build-up on the rear quarter panel fascias
• The rear quarter panel radar beams are obstructed or partially
obstructed by an adjacently parked vehicle or object.
• Approaching vehicles passing at speeds greater than 15 mph
(24 km/h)
• Severe weather conditions
• Driving in reverse faster than 3 mph (5 km/h)
• Backing out of an angled parking spot
CTA false alerts
Due to the nature of radar technology, there may be certain instances
when the BLIS will alert with no object present when backing up. This
is known as a false alert. Some level of false alerts are normal.
Circumstances that may cause a false alert when backing up are backing
out of a garage, backing into a parking space, and objects very close to
the sensor. False alerts are temporary and self correct.
270
2011 Taurus
Owners Guide, 3rd Printing
USA (fus)