was straightened in 1924 and now is next to the southbound lanes of I-5. In this area, known as the Five-Mile Grade, the four-lane Ridge Route Alternate became the northbound lanes of I-5, while the added four-lane alignment, built to the east (next to the old Ridge Route), had lower grades and became the southbound (downhill) lanes to cut down on runaway trucks. Two bridges were built to allow traffic to cross to the left side. Near the north end of this area, the Ridge Route curves away from the newer bypass. The road enters the Angeles National Forest about south of Templin Highway, with the Forest Service road designation 8N04. Establishments in the forest included the National Forest Inn, Kelly's Half Way Inn, Tumble Inn, and Sandberg's Summit Hotel. The National Forest Inn was on the west side of the road. A popular place, composed of white clapboard buildings, it was described in a 1932 highway beautification pamphlet as "the sort of filling station that gets into a national forest and is no addition thereto". On October 14, 1932, a fire began in the garage, and took over a day to put out. When the Ridge Route Alternate bypassed the site to the west, the inn was not rebuilt, and all that remains are concrete steps. About north of the National Forest Inn is Serpentine Drive, where the road curves around the sides of hills as it climbs out of a low point in the route (about above sea level). North of the curves, the road passes through Swede's Cut, also called Big Cut, Culebra Excavation, or Castaic Cut. The cut was the largest on the route, with a depth of . Reservoir Summit, also called Reservoir Hill, is above sea level. The Reservoir Summit Café was a popular high-class restaurant on the east side of the road, closed in the late 1920s; the foundation remains. The summit was named after a now-dry reservoir, one of three probably built for the concrete used in paving the road. Kelly's Half Way Inn was roughly halfway between Los Angeles and Bakersfield, on a small knoll with a single tree on the east side of the road; all that remains is remnants of the foundation. The Tumble Inn, later Mountain View Lodge, was on the west side of the road, and closed when the Ridge Route Alternate opened in 1933. Steps, including