My oil change ramps are made from 2x8's. (1) 3' (1) 2' and (1) 1' per ramp nailed together. They give an extra 4-1/2" clearance. I beveled the leading edge of each piece so the transition would be smoother. With the 2x8's flat on the ground, there is nothing that could possibly fail. They are completely solid. I did not add a built-in stop at the end for the tire to hit. If I had to do it over, I would add one so there is no guessing how far I'm on the last foot of ramp before driving over the edge.(I have not done that...yet)