At the [Furlo Pass][1] in the Apennines, the [Via Flaminia][2] passes through a tunnel built in 76 - 77 AD during the time of Emperor [Vespasian][3], replacing an earlier tunnel.

[![Via Flaminia tunnel][4]][4]

*[The tunnel built during the time of Vespasian][5]. Attrib: By AlMare (Own work) [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons*

This earlier, smaller (first) tunnel is "apparently of the 3rd century BC" according to the Wikipedia articles on [Tunnels][6] and the Via Flaminia, with the former article stating this is "*one* of the first road tunnels" (my highlighting). The article on the Furlo Pass states this smaller tunnel dates "from Etruscan times", as does the article on the [Apennine Mountains][7]

Did the [Etruscans][8] really build a tunnel here and, if so, is it the first known road tunnel built?

If not, what is the earliest known road tunnel built under or through a natural formation (i.e. not under or through a man-made construction)?

**EDIT**

In his answer, Alex makes the valid point that it is not exactly clear what a road is. There are various definitions depending on what source one looks at.

 - [Merriam-Webster][9] has "**an open way for vehicles, persons, and
   animals**"
 - [Oxford][10] offers "**A wide way leading from one place to another,
   especially one with a specially prepared surface which vehicles can
   use**" (Collins and Cambridge have similar definitions).
 - **[Wikipedia][11]: "A road is a thoroughfare, route, or way on land between two places that has been paved or otherwise improved to allow
   travel by foot or some form of conveyance**".

For the purposes of this (historical) question, any of the aforementioned definitions are acceptable. However, I would exclude tunnels built for mining.


  [1]: https://en.wikipedia.org/wiki/Furlo_Pass
  [2]: https://en.wikipedia.org/wiki/Via_Flaminia
  [3]: https://en.wikipedia.org/wiki/Vespasian
  [4]: https://i.sstatic.net/fNiUk.jpg
  [5]: https://commons.wikimedia.org/wiki/File:Furlo_Tunnel_North.jpg
  [6]: https://en.wikipedia.org/wiki/Tunnel#Antique_and_early_middle_ages
  [7]: https://en.wikipedia.org/wiki/Apennine_Mountains
  [8]: https://en.wikipedia.org/wiki/Etruscan_civilization
  [9]: https://www.merriam-webster.com/dictionary/road
  [10]: https://en.oxforddictionaries.com/definition/road
  [11]: https://en.wikipedia.org/wiki/Road