Europeans like to talk about self-explaining roads, where road design and environment suggests safe driving speeds. Americans and Australians like forgiving roads, where the road design minimises the result of driving mistakes.
Research in Connecticut (115 pages) shows that roadway type and building setbacks influence car speeds. But the biggest factor in slowing down drivers is cars parked at the side of the street, which reduces driven speeds by up to 10%. A summary can be found in the American Infrastructurist.