I saw some DIY ramps built from woof online that allowed you to move the ramp portion for easier access, especially under lower cars. FYI.
https://www.google.com/search?q=diy+car+ramps&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari#fpstate=ive&vld=cid:e697f294,vid:be0XKNrNaXE,st:0