Problem 5-18.

No, to an observer standing still on the ground (i.e. in an inertial frame), there is no outward force pressing the passenger against the wall. The passenger exerts an outward force to the wall and by Newton's third law (action and reaction) the wall exerts an normal force to the passenger. This normal force acting on the passenger is inward (not outward) towards the center and it is this normal force that causes the centripetal acceleration.

The passenger does experience an outward force (centrifugal force) in feeling. However, this force is "fictitious" because the passenger is in an accelerating (i.e. non-inertial) frame.