FORD 2010 Taurus v.2 - Manual (Page 271)

The CTA system detects vehicles approaching up to 45 feet (14 meters)
away (approximately the width of five parking spaces). Coverage
decreases when vehicles and objects in close proximity block the CTA
sensors (refer to figure for approximate zone coverage areas [sensor
obstructed for vehicle on left]). Backing slowly from the parking spot
in these situations helps to increase the sensor coverage and
effectiveness.
Driving
271
2010 Taurus (500)
Owners Guide, 2nd Printing
USA (fus)