Those are almost the exact same steps (only minus one step) I used to use for my girl (short legs) in my last car. I've since gotten another SUV which is too tall for the steps. I am with the others that say the jump into a high car is undue stress on their joints. Both of my dogs are over 90#.
I had heard a ramp is better for dogs with arthritis (she now gets a bit stiff every once in a while) so I purchased one for the new vehicle. One of the main complaints about the type I bought (by Solvit) was the "sandpaper" type surface on it. She wouldn't budge on it. I added carpet on top of it and did as a few others said--had her walk on it while it was flat on the ground. After that, I placed it in position on the car, put her leash on, and stood next to it so she COULDN'T jump off. Oh...a few treats and praising helped too!