Caltrans District 8 will upgrade nearly eight miles of SR 173 from Route 138 to east of Arrowhead Lake Road, boosting safety and ride quality for local commuters
Caltrans / SR-173 pavement project (Courtesy Caltrans)Hesperia, California (Our Hesperia) – Caltrans District 8 is set to begin the SR-173 pavement project in July 2025, repaving the highway from Route 138 through Hesperia to half a mile east of Arrowhead Lake Road to improve safety and ride quality for commuters and recreational visitors alike.
Background on SR 173
State Route 173 spans roughly 25 miles entirely within San Bernardino County, beginning at SR 138 near Silverwood Lake in Hesperia and ending at SR 18 south of Lake Arrowhead. The highway passes through rural foothills, parkland, and forest, and features the only unpaved, one-lane jeep trail segment in California, which has been closed since 2011. While much of SR 173 remains a scenic byway, aging pavement and winter weather have left portions in need of rehabilitation.
Details of the SR-173 Pavement Project
Caltrans Project ID 1001001, advertised April 7, 2025, will cold-plane the existing asphalt concrete pavement, install new HMA (Type A) surfacing, and replace the AC topping across the 7.7-mile segment of SR 173. Work extends from the junction with Route 138 at post-mile L0.0 through post-mile L7.7, just east of Arrowhead Lake Road. Project advertising in spring allows Caltrans to secure contractors and order materials, ensuring crews mobilize promptly when work begins in July.
Expected Benefits and Safety Improvements
Pavement resurfacing will enhance ride smoothness, reduce vehicle wear, and improve drainage to lessen hydroplaning risks during rainstorms. New asphalt mix specifications meet Caltrans durability standards, extending the pavement life by up to 15 years and cutting maintenance needs. Additionally, refreshed pavement markings and rumble strips will help drivers stay centered in their lanes, reducing collision risks on Hesperia’s rural highways.
Traffic Impacts and Detours
During construction, SR 173 will undergo alternating lane closures and daytime flagging operations to maintain safe work zones. Motorists may experience delays of up to 20 minutes; Caltrans recommends detouring via I-15, I-215, and SR 210 for through traffic heading toward Lake Arrowhead. Local access to residences and businesses along SR 173 will be maintained outside active paving hours, with flaggers controlling one-way traffic.
Funding and Timeline
The SR-173 pavement project is funded through the State Highway Operations and Protection Program (SHOPP), which dedicates billions annually to maintain California’s highway network. Construction is slated to begin in July 2025, with completion expected by late fall, weather permitting. Ongoing monitoring and quality control tests will ensure the new pavement meets state standards before reopening the full roadway.
Community Reaction in Hesperia
Local residents have welcomed the news of pavement upgrades. “Driving this stretch has become rough over the years—fresh asphalt will make our commute safer.
Long-Term Impact on Hesperia
Improved pavement will support economic growth by ensuring reliable travel for freight carriers and delivery vehicles serving Hesperia and surrounding communities. Enhanced roadway conditions may also attract new recreational visitors to nearby lakes and forest areas, boosting local hospitality revenues. In the longer term, reduced maintenance disruptions mean fewer closures and consistent travel times year-round.
