length width height
Your kidding, don't break your back nor waste your time and money, this is all you need. I got one and is perfect!
No it does not need to be secured, when you drive over the low front part, the weight of you car holds it in place. That being said I did secure it because it would get moved when I was doing other things in the garage and the car was not holding it down.
both side is preferable. Here's why.... one side is for smaller car and the other side is for a truck or wider base vehicle. If you have one car and always the same park there, then one is enough but I'd get two anyway to be sure.
I've been using the mat without gluing it down. It's staying in place every time that I've used it. You might want to try without gluing down.
12 inches wide, 18 inches long and 3 1\2 inches high