This pavement once carried US 97 traffic. By the 1960's this tunnel was too narrow for the truck traffic, so the highway was relocated to the base of the bluff. For a time before the relocation an alternating one-way traffic system through the tunnel was used. The highway had been becoming increasingly dangerous in the years leading up to the construction of I-82.
Remanants of post and cable guardrail can be found at the edge of the pavement.
A cose-up view of the old tunnel. I believe this tunnel was once timbered.