In a truly libertarian society the roads would be privately owned and the clearance of the roads would be the responsibility of the road’s owner.
Murray Rothbard addresses private roads in his Libertarian Manifesto
http://mises.org/document/1010/For-a-New-Liberty-The-Libertarian-Manifesto
http://mises.org/rothbard/newlibertywhole.asp
Here is an audio link to the section on roads:
http://mises.org/media/1773/11-The-Public-Sector-II-Streets-and-Roads
