California State Route 173
|Defined by Streets and Highways Code § 473|
|Maintained by Caltrans|
|Length||24.944 mi (40.143 km)|
|West end||SR 138 in Hesperia|
|East end||SR 18 near Lake Arrowhead|
State Route 173 (SR 173) is a state highway in the U.S. state of California that runs entirely in San Bernardino County, mostly in the San Bernardino National Forest. Its west end is at State Route 138 near the west end of Silverwood Lake in the Summit Valley south of Hesperia. Its east end is at State Route 18 south of Lake Arrowhead. The route starts at the Mojave River Forks, skims the easterly and southerly sides of Lake Arrowhead and meets State Route 189, Lake's Edge Road, at the south entrance to the Lake Arrowhead mall
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. 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.
SR 173 begins at SR 138 just inside the Hesperia city limits and travels east along the shore of Silverwood Lake, passing near Cedar Springs Dam. 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. A few miles from Lake Arrowhead, SR 173 becomes paved 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.
SR 173 is not part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. SR 173 is eligible for inclusion in the State Scenic Highway System, but it is not officially designated as a scenic highway by the California Department of Transportation.
This section needs expansion. You can help by adding to it. (March 2010)
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 (between Postmile 7 and Postmile 11) unsafe for passage from erosion and storm damage. As of March 2011, the one-lane trail portion of SR 173 is permanently closed to through traffic. 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.
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 an overlap due to a correction or change, and T indicates postmiles classified as temporary ( ). Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in San Bernardino County.
|Hesperia||L0.00||SR 138 to I-15 – Silverwood Lake, Crestline||West end of SR 173|
|||L6.99||Arrowhead Lake Road – Hesperia|
|One-lane, unpaved segment, closed|
|Lake Arrowhead||21.46||SR 189 – Blue Jay|
|||23.04||SR 18 – Running Springs, Big Bear Lake, San Bernardino||East end of SR 173|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- California 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.
- San Bernardino County Road Atlas (Map). Thomas Brothers. 2008.
- Federal Highway Administration (March 25, 2015). National Highway System: California (South) (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration.
- 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.
- "Article 2.5 of Chapter 2 of Division 1". California Streets & Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
- California Department of Transportation (August 2019). "Officially Designated State Scenic Highways and Historic Parkways" (XLSX). Sacramento: California Department of Transportation. Retrieved September 17, 2017.
- "State Route 173 (Unpaved Portion) Permanent Closure" (PDF). CalTrans District 8. Retrieved 18 December 2012.
- California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
- California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
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