Ford 2010 Fusion Hybrid Owner's Manual page 229

Driving
The Cross Traffic Alert 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 Cross Traffic Alert sensors (refer to figure for approximate zone
coverage areas [sensor obstructed to vehicle on left]). Backing
slowly from the parking spot in these situations helps to increase the
sensor coverage and effectiveness.
Cross Traffic coverage also decreases when parking at shallow angles
(refer to figure for approximate zone coverage areas [sensor
obstructed to vehicle on left]).
229
2010 Fusion Hybrid (hfv)
Owners Guide, 1st Printing
USA (fus)