Skip to main content

Patterson Pass Road

Recently on a day trip to the San Francisco Bay Area I traversed the Diablo Range eastbound via Patterson Pass Road.


Patterson Pass Road is an approximately 13 mile roadway which starts at Mines Road in Livermore of Alameda County.  Patterson Pass Road eastward ascends over the approximately 1,600 foot namesake Patterson Pass into San Joaquin County where it ends at Interstate 580 near Tracy.  Patterson Pass Road has an infamous reputation as being a dangerous roadway due to the lengthy one-lane section and heavy rush-hour commute traffic.

Patterson Pass is one of the earliest documented European paths of travel over the Diablo Range as it was explored during the 1775-1776 Spanish Expedition led by Juan Bautista de Anza.  The 1775-1776 Spanish expedition charted out much of San Francisco Bay which led to the founding of the Presidio of San Francisco and Mission San Francisco de Asis.  Patterson Pass Road between Cross Road east to Midway Road is part of the Juan Bautista de Anza National Trail.  The Juan Bautista de Anza Trail is a 1,210 mile Auto Touring Route organized by the National Park Service which closely follows the 1775-1776 Spanish expedition from modern day Tubac, Arizona to the San Francisco Bay Area.  More information regarding the Juan Bautista de Anza National Historic Trail can be found on nps.gov and cahighways.org.

nps.gov on Juan Bautista de Anza National Historical Trail

cahighways.org on Juan Bautista de Anza National Trail in California

Patterson Pass ultimately didn't become part of the inland route of travel between the Spanish Missions on El Camino Viejo.  The route of El Camino Viejo was to the south over Corral Hollow Pass via what is now Signed County Route J2 on Tesla Road.   The earliest highway map I can find clearly showing Patterson Pass Road is a CSAA edition from 1917.

1917 CSAA State Highway Map

Patterson Pass Road can be seen on the 1935 California Division of Highways Mas of Alameda County.

1935 Alameda County Highway Map

My approach to Patterson Pass Road was from southbound Vasco Road in Livermore.  I made a left hand turn from Vasco Road onto Patterson Pass Road eastbound.



Patterson Pass Road between Vasco Road east to Greenville Road four-lanes and is directly north of Lawrence Livermore National Laboratory.



At Greenville Road the path of Patterson Pass Road drops to two lanes and exits the City of Livermore.



Patterson Pass Road east of Greenville Road to Cross Road has numerous road safety features.  Most of the traffic control measures seem to be oriented at slowing down commuter traffic.







East of Cross Road the alignment of Patterson Pass Road drops to a single lane and picks up the Juan Bautista de Anza National Historic Trail.  Patterson Pass Road is a wide single lane and quickly ascends to Patterson Past.














Patterson Pass has a wide shoulder that is worth pulling over to see as there is two wide vistas.  This view is from Patterson Pass looking west towards Livermore Valley.


The sharp descent in Patterson Pass Road eastward from the top of Patterson Pass is very dramatic to the eye.


From Patterson Pass almost all of the Altamont Pass Wind Farm can be seen.  The Altamont Pass Wind Farm was commissioned in 1981 and now consists of 4,930 wind mills which are capable of producing 576 Megawatts of electricity.


The eastward drop on Patterson Pass Road is fast and rolls through the hill side.


















As Patterson Pass Road approaches Midway Road the Altamont Pass Wind Farm sub-station can be seen at the former rail siding location Midway . Patterson Pass Road crosses under a Union Pacific rail underpass which originally part of the Western Pacific Railroad.






At Midway Road the Juan Bautista de Anza National Historic Trail splits off of Patterson Pass Road.  Patterson Pass Road expands back out to two-lanes approaching the San Joaquin County Line.



Patterson Pass Road continues eastward to I-580 as a normal two-lane roadway.





Comments

Popular posts from this blog

The original alignment of California State Route 1 in San Francisco

In 2019 the Gribblenation Blog Series covered the history of the Hyde Street Pier and the original surface alignment of US Route 101 in San Francisco.  Given the Golden Gate Bridge opened to traffic in May of 1937 coupled with the fact that the Sign State Routes had been announced in August of 1934 there were still some open questions regarding the original highway alignments in San Francisco.  Namely the question of this blog is; where was California State Route 1 prior to the completion of the Golden Gate Bridge?  Thanks the to the discovery of a 1936 Shell Highway Map of San Francisco and the California Highways & Public Works the answer can be conveyed clearly.     Part 1; the history of early California State Route 1 in San Francisco The genesis point for California State Route 1 ("CA 1") in San Francisco dates to 1933.  1933 was significant due to the State Legislature allowing the Division of Highways to assume maintenance of highways in Cities for the first time. 

Former California State Route 24 through the Kennedy Tunnel and Old Tunnel Road

 Near the eastern City Limit of Oakland high in the Berkeley Hills one can be find the ruins of the Kennedy Tunnel at the intersection of Old Tunnel Road and Skyline Boulevard.  The Kennedy Tunnel opened in 1903 and was the first semi-modern automotive corridor which crossed the Alameda County-Contra Costa County Line.  The Kennedy Tunnel even saw service briefly as part of California State Route 24 before the first two bores of the Caldecott Tunnel opened in 1937.   Part 1; the history of the Kennedy Tunnel The genesis point for California State Route 24 ("CA 24") being extended into the San Francisco Bay Area begins a couple years before the Sign State Routes were announced when Legislative Route Number 75 ("LRN 75") was added by 1931 Legislative Chapter 82.  According to cahighways.org the original definition of LRN 75 was as simply "Walnut Creek to Oakland."  The instigator for the adoption of LRN 75 was construct a replacement route for the Ken

Santa Clara County Route G8 and the New Almaden Quicksilver Mine

Santa Clara County Route G8 is a 29.38 mile County Sign Route which is part of the San Francisco Bay Area transportation corridor.  Santa Clara County Route G8 begins at California State Route 152 near the outskirts of Gilroy and terminates at former US Route 101 at 1st Street/Monterey Road near downtown San Jose.  Santa Clara County Route G8 incorporates the notable Almaden Expressway and is historically tied to the New Almaden Quicksilver Mine.   (Santa Clara County Route G8 map image courtesy CAhighways.org) Part 1; the history of Santa Clara County Route G8, the Almaden Road corridor and New Almaden Mine The present corridor of Santa Clara County Route G8 ("G8") began to take shape with the emergence of the Almaden Expressway.  According to the October 1960 California Highways & Public Works Unit 1 of the Almaden Expressway opened in November of 1959 between Alma Avenue near downtown San Jose south to the Guadalupe River as part of a Federal Highway Aid Secondary pro