There is a nice interactive by the National Association of Counties (by my former co-author Emilia Istrate and others): The Road Ahead which maps the variety of financing issues facing local governments in the US.

There is a huge variety of organization across the United States. The page notes:

The interactive provides individualized PDF profiles for 43 states where counties have authority over roads and/or bridges. Counties in four states (Delaware, North Carolina, Vermont and West Virginia) do not have authority over both roads and bridges. New Hampshire counties do not own roads and only one county (Belknap County) owns a bridge. Connecticut and Rhode Island do not have county governments and are not included in the study. They are marked in gray on the map.

So why do we need 3 or even 2 levels of government managing roads when some states can do with one? [See Jurisdictional Overload]. Should this be government owned (or executive branch controlled) at all when other utilities are cooperatively or privately managed and publicly regulated? In this era of declining demand for travel, it is seriously time to rethink how we manage roads. Some rationalization is in order.

See also Enterprising Roads.