The steepest road in the world thats paved and can theoretically be driven up is Baldwin Street in Dunedin, New Zealand. The road climbs 1m for every 2.86m travelled horizontally. Its so steep that the tarmac runs off before it sets so the road had to be concreted. Special grooves are cut into it to help cars get a grip but youd still want a reasonable amount of oomph under your cars bonnet before attempting this one.
