The Trajectory Guidance System allowed KITT to calculate the perfect trajectory so that the car could Turbo Boost out in a stationary position or if it was trapped under something.
Trajectory Guide button
Trajectory Guide determining the best angle to Turbo Boost.
("Big Iron"; "Blind Spot")
The Trajectory Guide was first used in "Blind Spot" when KITT had to leap out of a car compressor. But in "Big Iron", Michael says the Trajectory Guide is a new feature. This was because "Big Iron" was filmed at the beginning of the season but was not aired until the end, way after "Blind Spot" aired.