Why did Chevrolet build my air dam this way???

[euromodder]

Originally Posted by Shepherd777

But can you explain the termination 2/3rds. from the outside of the tire???

None of these are as wide as the tires are, though this seems to cover very little frontal area of the tire.
Usually they extend to about 2/3 of the tire width - the rest is done by the air being pushed out a bit further than the spats are wide.

This seems very narrow though.