The road authorities may permit any owner or lessee of land abutting both sides of a highway to tunnel under the highway for such purposes as the owner or lessee deems desirable in utilizing the lands. The tunnel and appurtenances thereto shall be constructed and maintained so as not to endanger or unduly inconvenience the public in the use of the highway and, except as hereinafter provided, shall be constructed by and at the expense of the owner or lessee.
The permit shall specify the location, size, kind, design, manner of construction of the tunnel, and such safeguards for the traveling public that the road authority deems necessary. All tunnels, bridges, and appurtenances thereto shall be constructed in accordance with the permit.
Any tunnel constructed as provided in this section under any highway shall be maintained by the road authority having jurisdiction over the highway. A town board may charge the costs of maintenance of the tunnel to the users if the users and the town board agree on the amount to be charged.
When any road authority determines that the construction of such tunnel is necessary for the safety and convenience of public travel, it may construct and maintain the tunnel, or it may enter into agreements with the abutting landowners for the equitable division of the costs of the construction.