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California State Route 37; the Blood Alley of San Pablo Bay

This past November I drove the entirety of California State Route 37 between Interstate 80 in Vallejo to US Route 101 near Novato.  CA 37 west of the Napa River to CA 121 at Sears Point is known as the "Blood Alley of San Pablo Bay."


CA 37 is an 21 mile east/west State Highway which connects I-80 in Vallejo of Solano County west to US 101 near Novato of Marin County.  CA 37 has an 11 mile segment west of US 101 that is unbuilt towards planned CA 251 (formerly planned CA 17) near Nicasio.  



Part 1; the history of CA 37, the Sears Point Toll Road, CA 48, CA 121, and the "Blood Alley"

What is now CA 37 between US 101 and CA 121 entered the State Highway System as part Legislative Route 8.  LRN 8 was defined as part of the 1909 First State Highway Bond Act as a highway routed between LRN 1 in Ignacio east to Cordelia by way of Napa at Legislative Route 7.  LRN 8 can be seen on the 1918 Division of Highways State Map


In a August 1934 Department of Public Works Guide CA 37 was announced as one of the original Sign State Routes.  CA 37 was routed between Ignacio on LRN 8 to Sears Point, LRN 8 to Napa, and LRN 6 to CA 28 near Monticello. 



According to CAhighways.org a Legislative Chapter in 1921 authorized the Department of Engineering to "to make an investigation and submit a preliminary report upon a proposed state road with the necessary bridges connecting the city of Vallejo with a point on the state highway near Sears Point in Sonoma County."  This roadway wasn't built as a State Highway but rather as Sears Point Toll Road which opened to traffic in 1928 according to the Novato History website.  The Sears Point Toll Road was operated by Golden Gate Ferries under the subsidiary Sears Point Toll Road Company.  The Sears Point Toll Road can be observed on the 1935 Division of Highways Map of Solano County and Sonoma County. 





The California Transportation Commission recommended the State purchase the Sears Point Toll Road in late 1932.  The purchase of the Sears Point Toll Road required Naval approval due to the Mare Island Naval Shipyard being located on the highway.  The Sears Point Toll Road was purchased by the State in late 1938.  Ultimately the Sears Point Toll Road was incorporated into the State Highway System as Legislative Route 208 in 1939.  LRN 208 became the first iteration of what was CA 48 which was routed between CA 37 at Sears Point east to US 40 in Vallejo.  CA 48/LRN 208 first appear on the 1940 Division of Highways Map.


A September/October 1944 California Highway and Public Works Guide discusses the difficulty in maintaining CA 48/LRN 208 during World War II due to the high traffic into the Mare Island Naval Yard.  A new bridge over the Napa River is discussed but the project ultimately rejected in favor of resurfacing the existing structure.  An expansion of CA 48/LRN 208 eastward with a grade separation towards US 40 is discussed.  This expansion of CA 48/LRN 208 east of the Napa River to US 40 was the genesis point of the present freeway grade of CA 37 in Vallejo. 




The World War II era improvements to CA 48/LRN 208 can be seen by comparing the 1940 Division of Highways Map to the 1942 Edition.  The 1942 edition shows most of CA 48/LRN 208 from the Sonoma County Line eastward paved in concrete.  This new concrete section of CA 48/LRN 208 would later become famous as the "Blood Alley of San Pablo Bay" as part of CA 37.

1940 Map


1942 Map



The July/August 1950 California and Public Works Guide discusses the improvements of CA 37/LRN 8 on the Black Point Cut-Off between US 101 east to CA 48 at Sears Point.  The improvement project expanded part of CA 37/LRN 8 to a four lane expressway while at the same time eliminated some of the higher grades that were a problem on the original highway. 











In a March/April 1957 California Highway and Public Works Guide the expansion of the Black Point Cut-Off Expressway portion of CA 37/LRN 8 is cited.  Specifically the replacement of the Petaluma Creek Bridge with a four lane span is discussed.  



The March/April 1958 California and Department of Public Works Guide discusses the construction of the Petaluma Creek Bridge on CA 37/LRN 8.   The new Petaluma Creek Bridge would be completed in 1958.





A March/April 1960 California Highway and Public Works Guide discusses the Black Point Cut-Off section of CA 37/LRN 8 along with the potential for a future six lane freeway.  The final phase of the Black Point Cut-Off expressway portion of CA 37/LRN 8 is described as being completed in June of 1959.


In 1959 according the second Legislative Route 252 was defined as a new State Highway between US 101 west to planned CA 17.  LRN 252 was intended to be part of CA 37 and first appears on the 1960 Division of Highways State Map.   


The July/August 1963 California and Public Works Guide describes the substructure of the new Napa River Bridge on CA 48/LRN 208.  The new Napa River Bridge substructure was completed in April of said year and the span was intended to replaced the original 1927 bridge.  The 1927 Napa River Bridge was a bascule lift span and original to Sears Point Toll Road. 










During the 1964 State Highway Renumbering CA 37 was realigned directly east from Sears Point via what had been CA 48/LRN 8.  CA 37 northeast of Sears Point on LRN 8 was renumbered to CA 121.  Unbuilt LRN 252 was changed to legislatively to CA 37.  All these changes can be seen on the 1964 Division of Highways State Map


The last mention of the new Napa River Bridge appears in the November/December 1965 California Highway and Public Works Guide as funded for 1966/1967.  


The new Napa River Bridge appears as four lane freeway on the 1969 Division of Highways Map


Beginning in the 1960s CA 37 between Sears Point and Mare Island began to see an increasingly high rate of fatal accidents which led to it being coined the "Blood Alley of San Pablo Bay."  A crossover barrier was proposed by local resident Jim Poulous after his son died on Blood Alley in a traffic accident in 1993.  According to CAhighways a crossover barrier on CA 37 was installed in Blood Alley as of 2004 which greatly reduced the number of fatal accidents. 

According to CAhighways.org CA 37 was built to full freeway standards from Mare Island east to I-80 as of 2006.  As of late much of the discussion with CA 37 has been oriented towards upgrading the highway near Novato and through Blood Alley due to increasing flood concerns.  Much of the discussion through the legislative channels has been regarding using viaduct/causeway structures to raise CA 37.  The crux of the argument for an elevated viaducts and/or causeway seems be aided by environmental concerns since a newer facility is likely to improve the conditions of the waterways on San Pablo Bay.  CAhighways has an extensive list of proposals pertaining to the future of CA 37.  


Part 2; a drive on CA 37 from I-80 to US 101

My approach to CA 37 westbound was from I-80 eastbound in Vallejo.  CA 37 westbound is accessed via overpass from I-80 eastbound at Exit 33. 







CA 37 west crosses over I-80 and at Exit 20 Discovery Kingdom via Fairgrounds Drive can be accessed.  






CA 37 westbound accesses CA 29/Sonoma Street at Exit 19. 




CA 37 westbound begins to approach the Napa River.  At Exit 18 CA 37 accesses Wilson Avenue and Sacramento Street.  





CA 37 westbound ascends over the Napa River Bridge onto Mare Island.  CA 37 Exit 17 is signed as access to a Vista Point and Mare Island itself.  Suffice to say the Vista Point has seen much better days.  











CA 37 westbound drops to two lanes and enters Blood Alley.  As noted above the concrete crossover barrier in Blood Alley obstructs passing. 




CA 37 west through Blood Alley is aligned through the San Pablo Bay National Wildlife Refuge.  At Post Mile SOL 1.674 CA 37 westbound intersects Skaggs Island Road.  










CA 37 west ascends over Sonoma Creek into Sonoma County via the Richard Jansen Bridge. 







CA 37 west exits Blood Alley and meets CA 121 at Sears Point approximately at Post Mile SON 3.984.  









CA 37 westbound expands to four lanes on the Black Point Cut-Off Expressway.  CA 37 westbound ascends over Sears Point and is co-signed with El Camino Real Mission Bells which denote it's historic significance.  




CA 37 westbound is aligned through a low lying valley before rising over Petaluma Creek into Marin County/Black Point via the 1958 Petaluma Creek Bridge. 











CA 37 westbound descends from Black Point into the City Limits of Novato at approximately Post Mile MRN 13.683.







CA 37 westbound terminates at US 101 in Novato. 





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