That's dangerous
I don't know about that... it worked fine for Rowan Atkinsen, aka Mr Bean. He went to a store, bought a huge comfy chair that wouldn't fit in his car, mounted it on his roof, and then drove around [very hilly area] somewhere in London perhaps. He used a broom or mop to manage the brakes, a brick for the accelerator [those little EU cars don't need no stinkin japanese cruise control]. His feet I think somehow reached the steering column.
LoL. I saw that episode!