A visual confirmation evaluating apparatus generates unobstructed state information indicating that a driver in a vehicle at an intersection is in a position capable of visually confirming roads on the right and left. The air damping shockproof structure includes a top portion, a side portion, and a bottom portion, and an air chamber array disposed in the top portion. When the completely-fitted condition is achieved, this deflection prevention rib is slid under the lock arm to prevent the deflection of the flexible lock arm.