Category Archives: Tunnel

A tunnel on US 80?

In the late 1940’s, plans were being drawn for improvements to US 80 in San Diego County. The highway, as it was then, had changed little since its last upgrade between 1928 and 1932. While much of the highway was on a better alignment than before, the section between Alpine and Descanso still needed more work done. This part of the roadway still had sharp curves and steep grades. The combination of these conditions, including increasing traffic, made it rather treacherous at times.

Portion of the highway plans showing the realignment between Willows and Ellis.

In 1950, the first phase of improvements were made to this segment of highway. Beginning near the present-day West Willows interchange, a new alignment was constructed. This new alignment had a shallower grade than the original alignment. It was also a lot straighter. It followed eastbound I-8 until near East Willows. At the present-day East Willows interchange, the alignments met again. From there, the old alignment was straightened quite a bit. Portions of this new alignment are still in use as the westbound lanes of I-8.

Detail view of the tunnel location. West portal is located at the arrow.
Aerial photo of Deadman’s Curve near Viejas, CA. Note the provisions built for the tunnel on the west (left) side of the large curve.

At the large curve, known as “Dead Man’s Curve”, the 1950 improvements ended. It was at that curve, however, that a tunnel was planned to be constructed. The tunnel was a part of an additional phase of improvements that were never constructed. It would have been about 800 feet long and two lanes wide. I have not found any drawings of what the tunnel may have looked like. Most likely, however, it would have had a stone-faced portal, similar to other tunnels constructed around that time. Grading for the tunnel was partially done on the west side, though nothing was done on the east end.

Plans for the Sweetwater River Bridge near Los Terrinitos. Note the proposed alignments on either side of the bridge.

East of the tunnel, the alignment would have taken a different course. Instead of following the original alignment, a new one would be built, similar to the I-8 alignment, but rejoining US 80 near Los Terrinitos. There, a new bridge was constructed over the Sweetwater River bridge, bypassing the original 1917 bridge to the south. East of Descanso, another realignment was planned, though no provisions for this ever got past the planning stage. This bridge, along with the improvements to the west, were planned to be a part of an eventual US 80 expressway or freeway alignment. All of these plans were put on hold as other projects in the region.

When plans shifted from upgrading US 80 to the construction of a brand new freeway, the tunnel plan was scrapped. Instead of a tunnel, a deep cut would be dug into the mountain, allowing for a more even grade across the area. The alignment chosen also reduced the number of river crossings from three to one. The freeway alignment also bypassed the section of US 80 through Guatay. In doing so, it had to cross Pine Valley creek at a rather deep section. The valley was bridged using a new method called “Segmental Balanced Cantilever”, which resulted in the highest bridge on the Interstate system at 450 feet above the floor of the canyon.

Plans for I-8 between West Willows and State 79 (Descanso)
Detailed plans for the tunnel area showing the old alignment in relation to the present freeway.

Today, little remains of the tunnel’s planned location. Only vestiges of the old alignment can be seen around the large cut where the tunnel was planned. A vista point was constructed within the cut as well, at the edge of which a portion of the original alignment can be seen. I-8 also utilizes a portion of the 1950’s alignment. From near Viejas Creek to just west of East Willows, the two outermost lanes of I-8 eastbound mostly use the 1950’s concrete, with portions replaced and a new lane added to the left. From East Willows to near the Vista Point, westbound I-8 follows the 1950’s alignment, while not using the paving as it does to the west, it does follow the grade. You can see this in the road cuts as the style of cut is different between each side of the freeway.

Following US 80 and its history across the mountains east of San Diego is fascinating. As technology progressed, each alignment became better and easier to travel. Unlike many other highways in California, US 80 didn’t go through an expressway phase. It went from a two lane highway to a four lane freeway on a new alignment. In doing so, the brief period when the original alignment was to be upgraded brought some interesting ideas. The tunnel, as well as some of the extra bridges planned, were a part of those ideas. They would be lost to time if it weren’t for a few bits of information on roadway plans from that era. In time, I may uncover yet more mysteries and unbuilt sections of the highway still unknown.