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California State Route 120

Route map:
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State Route 120 marker
State Route 120
Map
SR 120 highlighted in red
Route information
Maintained by Caltrans
Length152.562 mi[1] (245.525 km)
(Does not include the portion in Yosemite)
Existed1934–present
Tourist
routes
  • Tioga Road/Big Oak Flat Road
  • Lee Vining Canyon Scenic Byway
RestrictionsSegments through Tioga Pass, and between Mono Lake and Benton, closed in winter
Major junctions
West end I-5 in Lathrop
Major intersections
East end US 6 at Benton
Location
CountryUnited States
StateCalifornia
CountiesSan Joaquin, Stanislaus, Tuolumne, Mono
Highway system
← SR 119→ SR 121

State Route 120 (SR 120) is a state highway in the central part of California, connecting the San Joaquin Valley with the Sierra Nevada, Yosemite National Park, and the Mono Lake area. Its western terminus is at Interstate 5 in Lathrop, and its eastern terminus is at U.S. Route 6 in Benton. While the route is signed as a contiguous route through Yosemite, the portion inside the park is federally maintained and is not included in the state route logs. The portion at Tioga Pass at Yosemite's eastern boundary is the highest paved through road in the California State Route system. This part is not maintained in the winter and is usually closed during the winter season.

Route description

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Tioga Pass Entrance Station
SR 120 as Tioga Road by Tenaya Lake in Yosemite National Park.
California State Route 120 Markers at Yosemite National Park
Tioga road and Tenaya Lake viewed from Pywiack Dome.

SR 120 begins as a freeway intersecting Interstate 5 to extend Interstate 205 through Manteca. In east Manteca the freeway ends at SR 99 and becomes a highway which continues to head east through Escalon, Oakdale and other various small towns. East of Oakdale there are no highly populated areas for 90 miles (144 km) as it heads into the foothills of the Sierra Nevada and into Yosemite National Park. Entering Yosemite, SR 120 is known as Big Oak Flat Road as it heads towards Crane Flat. After leaving Crane Flat, Big Oak Flat Road turns southeast towards Yosemite Valley, while SR 120 continues east as Tioga Pass Road (or often simply Tioga Road).[2] The highway retains that name as it travels through Tuolumne Meadows, over Tioga Pass at an elevation of 9,945 feet, and through the Lee Vining Canyon on its 59-mile (95 km) journey to its intersection with U.S. Route 395, at Lee Vining. After a jog to the south along US 395, it continues east as Mono Mills Road,[3] skirting the south end of Mono Lake and providing access to the Mono Lake South Tufa as well as the historical site of Mono Mills before cresting Sagehen Summit and ending with the intersection of U.S. Route 6 at Benton. Both the portions through Yosemite National Park and the stretch between Mono Lake and Benton are subject to winter closure. Usually the highway is open through Tioga Pass by the Memorial Day weekend at the end of May, and typically closes for the winter sometime in November.[4][5]

Tioga Road/Big Oak Flat Road is officially both a National Scenic Byway and a National Forest Scenic Byway.[6] The segment through the Lee Vining Canyon between the eastern edge of Yosemite and US 395 is designated as the Lee Vining Canyon Scenic Byway, a separate National Forest Scenic Byway.[7]

SR 120 is part of the California Freeway and Expressway System,[8] and both the western portion and the eastern portion west of US 395 are part of the National Highway System,[9] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.[10] SR 120 is eligible to be included in the State Scenic Highway System,[11] but it is not officially designated as a scenic highway by the California Department of Transportation.[12] The Tioga Pass Road was designated as a California Historic Civil Engineering Landmark by the American Society of Civil Engineers in 2002.[13]

History

[edit]
Tioga Road, 1921.
The BLM Granite Mountain Wilderness is immediately north of Route 120, just east of Mono Lake.[14]

During the Gold Rush, SR 120 was originally known as Big Oak Flat Road, after the village of Big Oak Flat through which it passes in the Sierra foothills. It was a pack trail from Stockton which became popular with prospectors about 1849. By 1874 it was a wagon road which extended to Yosemite Valley.

In 1921, the California State Assembly authorized San Joaquin County to transfer the county road connecting Manteca with then-Route 5 (now I-5) at Mossdale to the state.[15] It was numbered Route 66, as was a 1933 extension from Manteca east to Route 13 in Oakdale. Also in 1933, Route 40 was extended east from Mono Lake to Route 76 (US 6) at Benton.[16] The route from Manteca to Benton was marked as Sign Route 120 in 1934,[17] and was soon extended west to Mossdale,[18] replacing what had been part of U.S. Route 99W.[19]

Priest grades

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West of Priest is a section of highway with over one hundred curves and hairpin turns, known as the "New Priest Grade." With a 4% grade, it opened in 1915 and was built by a group of local volunteers who desired an alternative to the very steep (17%) Old Priest Grade.[20] Today, both grades are paved, but trailers and RVs are prohibited from Old Priest Grade.[21] There is a 7,500-pound weight limit on the old grade.

New Tioga Road Construction, 1958-1961

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In 1956, National Park Service developed plans to relocate the Big Oak Flat Road from Crane Flat to the park's eastern boundary, and reconstruct the unimproved central section of the Tioga Road. NPS management wanted to "open up" the High Sierra section of the park to vastly increased numbers of visitors, and planned a new visitor center and other facilities at Tuolumne Meadows, as well as campgrounds and other facilities along the Tioga Road. This brought fierce opposition from the Sierra Club, led by famed photographer Ansel Adams. Adams and his supporters opposed the blasting of a great granite dome southwest of Tenaya Lake, as well as routing the highway along the western shore of the lake. Internally, however, many Sierra Club members supported the project. At the time, Sierra Club opposition created a serious rift in the long-time close relationship between the environmental organization and the National Park Service. In the end, the government proceeded to build the project as originally planned, with only minor modifications.[22]

California's first diverging diamond interchange

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On November 25, 2020, the first diverging diamond interchange in the state of California opened to traffic at the interchange with Union Road (exit 4) in Manteca.[23]

Major intersections

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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 numbers reset at county lines; the start and end postmiles in each county are given in the county column.

CountyLocationPostmile
[1][24][25]		Exit
[26]		DestinationsNotes
San Joaquin
SJ R0.49-21.18		LathropR0.491 I-5 – San Francisco, Los Angeles, Stockton, SacramentoWestbound exit and eastbound entrance; signed as exits 1A (south) and 1B (north); west end of SR 120; former US 50 west; I-5 exit 461
MantecaR1.331CYosemite AvenueSigned as exit 1 eastbound
​2McKinley AvenueInterchange under construction[27]
R3.323Airport Way (CR J3) – Sharpe Depot
R4.314Union RoadDiverging diamond interchange: first one constructed in California and opened to traffic on November 25, 2020[23]
R5.315South Main Street
T6.87
5.82[N 1]		6
 SR 99 south – Modesto, Fresno, Los Angeles		West end of SR 99 overlap; SR 99 exit 241
6.65[N 1]
6.20		East end of freeway on SR 99

 SR 99 north / Yosemite Avenue – Sacramento, Central Manteca		Interchange; east end of SR 99 overlap; SR 99 exit 242
8.84 CR J5 (Jack Tone Road)
​11.64French Camp Road
Escalon​
 CR J6 / CR J7 north (Escalon-Bellota Road, McHenry Avenue) – Farmington, Modesto		West end of CR J7 overlap
R16.92
 CR J7 south (Main Street) / Kern Street		East end of CR J7 overlap
Stanislaus
STA 0.00-T18.17		​3.16
 CR J9 north (Valley Home Road) – Valley Home		West end of CR J9 overlap
​​
 CR J14 north (Twenty-Six Mile Road)		West end of CR J14 overlap
Oakdale5.12

 SR 108 west (F Street) / CR J9 / CR J14 south (Yosemite Avenue) – Modesto		West end of SR 108 overlap; east end of CR J9 / CR J14 overlap
Tuolumne
TUO R0.00-R41.52		​8.19 CR J59 (La Grange Road) – La Grange, MercedNorthern terminus of CR J59
​​ CR E15 (O'Byrnes Ferry Road) – CopperopolisSouthern terminus of CR E15
​12.08
 SR 108 east – Sonora		East end of SR 108 overlap
Chinese Camp15.52
 SR 49 north – Sonora		West end of SR 49 overlap
Tuolumne River / Don Pedro ReservoirR19.61James E. Roberts Bridge
​R23.90
 SR 49 south – Coulterville, Mariposa		East end of SR 49 overlap
Buck MeadowsR39.46
 CR J132 (Smith Station Road, Greeley Hill Road) to SR 132 – Coulterville, Merced		Eastern terminus of CR J132
Yosemite National Park East end of state maintenance at western park boundary
​Big Oak Flat Entrance Station; park fee or pass required for entry[28]
Mariposa
MPA R41.52-43.75		​

 Big Oak Flat Road to SR 41 / SR 140 – Yosemite Valley
​Tuolumne Grove
(winter closure gate near the eastern end of the grove)[5][29]
Tuolumne
TUO 43.75-R56.15		​Tioga Pass Entrance Station (closed in winters); park fee or pass required for entry[28]
​West end of state maintenance at eastern park boundary
Mono
MNO R0.00-58.99		​R8.54Westbound winter closure gate
Lee ViningR12.06
50.74[N 2]
 US 395 north / Airport Road – Reno		West end of US 395 overlap
June Lake Loop North Junction46.40[N 2]
 SR 158 south – June Lake		Northern terminus of SR 158
Mono Mills Junction45.96[N 2]
13.37
 US 395 south – Bishop		East end of US 395 overlap
​18.49Eastbound winter closure gate
​39.05Westbound winter closure gate
​51.86
 Benton Crossing Road to US 395 – Owens River, Crowley Lake
Benton58.99 US 6 – Tonopah, BishopEast end of SR 120
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
  1. ^ a b Indicates that the postmile represents the distance along SR 99 rather than SR 120.
  2. ^ a b c Indicates that the postmile represents the distance along US 395 rather than SR 120.

See also

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References

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  1. ^ a b c California Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original (XLS file) on September 5, 2015. Retrieved June 30, 2015.
  2. ^ "The Tioga Road; a History 1883-1961 (1961, 1980), "Reconstruction," by Keith A. Trexler". yosemite.ca.us.
  3. ^ "Floodgap Roadgap's Summer of 6 -- U.S. Highway 6, Part 1: US 6 in California (Bishop to Nevada State Line; Inyo County, Mono County)". floodgap.com.
  4. ^ "Winter Driving Tips". Caltrans. Retrieved January 2, 2023.
  5. ^ a b "Yosemite National Park Winter Road Closures". National Park Service. Retrieved January 29, 2023.
  6. ^ Staff. "Tioga Road/Big Oak Flat Road". America's Byways. Federal Highway Administration. Archived from the original on November 20, 2011. Retrieved November 29, 2011.
  7. ^ Staff. "Lee Vining Canyon Scenic Byway". America's Byways. Federal Highway Administration. Archived from the original on October 23, 2011. Retrieved October 23, 2011.
  8. ^ "Article 2 of Chapter 2 of Division 1". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
  9. ^ Federal Highway Administration (March 25, 2015). National Highway System: California (North) (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved September 30, 2017.
  10. ^ 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.
  11. ^ "Article 2.5 of Chapter 2 of Division 1". California Streets & Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
  12. ^ California Department of Transportation (August 2019). "Officially Designated State Scenic Highways and Historic Parkways" (XLSX). Sacramento: California Department of Transportation. Retrieved September 30, 2017.
  13. ^ "The Tioga Pass Road Historical Marker". The Historical Marker Database. Retrieved March 6, 2021.
  14. ^ "BLM Granite Mountain Wilderness". Archived from the original on August 28, 2016. Retrieved August 27, 2016.
  15. ^ Statutes 1921 p. 1627: State highway in San Joaquin County
  16. ^ California Department of Transportation, State Highway Routes: Selected Information, 1994 with 1995 revisions
  17. ^ Dennis, T.H. (August 1934). "State Routes Will Be Numbered and Marked with Distinctive Bear Signs". California Highways and Public Works. 11 (8): 20–21, 32. ISSN 0008-1159 – via Archive.org.
  18. ^ H.M. Gousha Company, California Archived October 13, 2007, at the Wayback Machine, 1942
  19. ^ American Association of State Highway Officials, log of U.S. Highways, American Highways, ca. 1932
  20. ^ "Priest Grade, Grizzly Gulch". Pine Mountain Lake Association. Archived from the original on October 4, 2013. Retrieved June 6, 2013.
  21. ^ "CA-120 E". Google, Inc. Retrieved June 6, 2013.
  22. ^ "Tioga Road (HAER No. CA-149)". Historic American Engineering Record, National Park Service, U.S. Dept. of the Interior. Retrieved October 8, 2024.
  23. ^ a b "State Route 120 / Union Road Interchange Project". City of Manteca. Retrieved February 14, 2024.
  24. ^ California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
  25. ^ California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
  26. ^ California Department of Transportation, California Numbered Exit Uniform System, SR-120 Eastbound and SR-120 Westbound, accessed February 2008
  27. ^ Wyatt, Dennis. "McKinley Interchange is Manteca Game Changer". Manteca/Ripon Bulletin. Retrieved January 6, 2024.
  28. ^ a b "Yosemite National Park Fees & Passes". National Park Service. Retrieved December 31, 2021.
  29. ^ "View of eastbound Tioga Road at the open winter closure gate east of Tuolumne Grove". Google Street View. October 2018. Retrieved January 2, 2023.
  • Map: "Stanislaus National Forest, California," U.S. Forest Service, 1979.
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