It is the only California state highway with an unpaved segment, which is a one-lane jeep trail on the northwestern face of the San Bernardino Mountains directly east of Summit Valley and northwest of Blue Jay. Since March 2011, this one-lane unpaved segment of SR 173 has been closed.[2] Through traffic should use SR 138 and SR 18. An alternate route from Hesperia to Lake Arrowhead would involve heading south on I-15, then south on I-215, then east on SR 210 in San Bernardino to reach the southern terminus of SR 18 at Waterman Road.
Route description
SR 173 begins at SR 138 just inside the Hesperia city limits and travels east near the shore of Silverwood Lake, passing near Cedar Springs Dam, several houses and ranches, and the historic Las Flores Ranch site. The road briefly turns north further into the Hesperia city limits, leaving the San Bernardino National Forest. SR 173 leaves the city and enters Mojave River Forks Regional Park, where it turns east and intersects Arrowhead Lake Road, which leads to the urban center of Hesperia. Once SR 173 intersects the Pacific Crest National Scenic Trail, it turns into a one-lane dirt road rising along the north face of the San Bernardino Mountains, first heading east to its apex before turning south to the Lake Arrowhead area. This one-lane dirt segment has been closed to traffic since March 2011.[2] The paved segment of SR 173 resumes northeast of Lake Arrowhead and enters the community of Cedar Glen, where it parallels the Lake Arrowhead shoreline and encounters Papoose Lake. The highway enters the community of Lake Arrowhead, where SR 173 intersects SR 189 and turns south to terminate at SR 18.[3]
The barrier at the eastern end of the closed unpaved segment of SR 173The eastern point along SR 173 where the pavement ends and the unpaved segment heads westThe western barrier along SR 173 where the closed unpaved segment begins and heads east
Before 1964, Route 173 was part of California Legislative Route 59; however, like a small number of other California State highways, it was not signed. From 1934 to the mid-1950s the part of Route 59 that is now Route 173 was designated by the California Division of Highways to be a segment of California sign route 2; however, signing did not occur. From the mid-1950s through July 1964, the Division of Highways changed the routing of future sign route 2 from the subject segment of Route 59 to Legislative Route 188, the segment of present California 138 between the junction of Routes 138 and 173 and Mount Anderson Junction, the junction of Routes 18 and 138 south of Crestline.
The highway has faced repeated problems since the 2003 Willow Fire that has made the one-lane unpaved trail portion (approximately between Postmile 7.5 and Postmile 11.5) unsafe for passage from erosion and storm damage. Since March 2011, the one-lane trail portion of SR 173 has been permanently closed to through traffic.[2] While roadway preservation maintenance (basic grading, debris clearance) is still done, this decision effectively ends all further interest to upgrade the segment to a 2-lane passable highway through state-funded projects.
Major intersections
Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers to an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see California postmile § Official postmile definitions).[1] Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in San Bernardino County.
^ abcCalifornia Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original(XLS file) on June 30, 2015. Retrieved June 30, 2015.
^Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
SR 138 in Hesperia
SR 18 near Lake Arrowhead
