Cameras not detecting movement

Hello all! I have two outdoor spot light cameras that aren’t picking up movement, especially when I know people and vehicles have been by (friends, ups, etc). The driveway one doesn’t pickup anything unless you’re directly in front of it. The other one is the same way, doesn’t pickup ups walking the through the grass (they park on the road). What can I do to adjust to detect people and vehicles? The cameras do a very good job of detecting motion in the flower pots below them. How close does a person or vehilce have to be to detect motion? Thank you!