Your eyes start to close as you drive your car because you’re getting drowsy. This is a very dangerous way to drive your car, especially since your car is missing its top and its bottom. This is no time to be getting drowsy. Keep your eyes open and drive for your life!
The reason you’re so drowsy, and also the reason your car is missing part of its bottom, is because you took one of the car’s tires and made a tire swing (すい) out of it. You’d been swinging on the tire swing all day and now you’re super drowsy and worn out.