said by Tabletop : I don't know what state and federal rules and regulations are but at the local level there must be some kind of contract agreement to allow isp's such as centurylink to run lines through right of ways.
CenturyLink is an ILEC. The former Qwest part was part of the original "Ma Bell" (AT&T), until AT&T was broken apart, and the former regional Bell became, "USWest". As such, it is/was regulated at the state level. Its two large sister Bells are, currently, AT&T and Verizon.
Addendum: CenturyLink also incorporates two non-Bell ILECs: CenturyTel and Embarq. I am not familiar with their regulatory history; but CenturyLink's geographic footprint is largest of all the ILECs