Good Parking Spaces - Can anybody give me a good design for a parking lot that allws more space and less accidents?

Can anybody give me a good design for a parking lot that allws more space and less accidents?

I need this for a math project! help!!!!!!i need the design for a parking lot avoiding accidents, waste of time and space

Give size. Usually Entering from the right and exiting on the left side of the parking lot. Parking Cars Vertically Head in ONLY. ONE WAY lines.