NDOT says the project extended the westbound Cave Rock tunnel entrance with a new 60-foot by 27-foot structure designed to catch falling rock before debris reaches the roadway. Contractor Q&D Construction used shotcrete on the exterior of the tunnel and hand-molded the surface to blend it in with the natural rockface surrounding the entrance.
The contractor also added lighting and white paint to the inside of both the westbound and eastbound tunnels to improve visibility. Also added were radar-activated overhead signs designed to notify drivers of issues such as potential icy conditions or bicyclists in the tunnels.
Other improvements included paved shoulders, new drop inlets, new sediment filtration systems, slope scaling and barrier rails.
The $6 million project came about as a result of problems arising from heavy rains during the winter of 2014-2015, including loosened boulders and rock debris.