Carquinez Bridge

The Carquinez Bridge is a pair of parallel bridges spanning the Carquinez Strait at the northeastern end of San Francisco Bay. They form the part of Interstate 80 between Crockett and Vallejo, California, United States.

The name Carquinez Bridge originally referred to a single cantilever bridge built in 1927, which was part of the direct route between San Francisco and Sacramento. A second parallel cantilever bridge was completed in 1958 to deal with the increased traffic.

Later, seismic problems made the 1927 span unsafe in case of an earthquake, and led to the construction, and 2003 opening, of a replacement: a suspension bridge officially named the Alfred Zampa Memorial Bridge, in memory of iron worker Al Zampa, who played an integral role in the construction of numerous San Francisco Bay Area bridges. The Alfred Zampa Memorial Bridge carries southbound traffic from Vallejo to Crockett, and the 1958 cantilever span carries northbound traffic.

The first regular crossing of the Carquinez Strait began in the mid-1800s as a ferry operated between the cities of Benicia and Martinez, six miles upstream from the bridge site. Auto service started on this route in 1913. A train ferry operated between Benicia and Port Costa from 1879 until 1930 when a rail bridge opened. Ferry service at the site of the bridge started in 1913 by the Rodeo-Vallejo Ferry Company.^[1]

The original steel cantilever bridge was designed by Robinson & Steinman and dedicated on May 21, 1927. Prior to this, crossing the Carquinez Strait necessitated the use of ferries. The bridge cost 8ドル million to build (equivalent to 140ドル.32 million in 2023). It was the first major crossing of the San Francisco Bay ^[2] and a significant technological achievement in its time.

Upon its completion, the span became part of the Lincoln Highway. This historic transcontinental roadway's original alignment, like the Transcontinental Railroad that preceded it nearly sixty years earlier, chose to avoid crossing the Carquinez Strait entirely. The preferred option, given the engineering limitations of the day, was to skirt around the Delta by going south from Sacramento through Stockton, then proceeding west across the San Joaquin River and over the Altamont Pass, and finally reaching Oakland from the south; a route that would later become U.S. Route 50 and ultimately Interstates 5, 205, and 580. This circuitous route, several miles longer, and traversing a rather formidable mountain pass, was preferable to crossing the Carquinez Strait, a deep channel with strong currents and frequent high winds. For decades, building a bridge across the Carquinez Strait was considered prohibitively expensive and technologically risky. Once the bridge was built however, driving from Sacramento to the East Bay became much more direct. The Carquinez Bridge provided a welcome alternative route from the Central Valley to the Bay Area, one that no longer required loading one's vehicle onto and off of a ferry. With the bridge completed, the Lincoln Highway was realigned to cross the Sacramento River, then proceed southwest through Davis and Vallejo, across the Carquinez Bridge, and along the shores of the San Pablo and San Francisco bays to Richmond and Oakland; becoming U.S. Route 40, and ultimately Interstate 80.

After the Loma Prieta earthquake engineers determined that the aging 1927 span was seismically unstable, and that a retrofit was impossible. The decision was made to replace it with a new suspension bridge. The 1927 span was temporarily used to hold eastbound traffic while the 1958 eastbound span underwent a seismic retrofit, deck and superstructure rehabilitation, and painting to extend its serviceable life.^[3] The old 1927 cantilever bridge was dismantled three years after the opening of its replacement; with completion on September 4, 2007. A 3,000-pound bronze bell atop one of the bridge piers was removed and placed into storage. The bell will eventually be displayed in a new museum to be built at the Oakland end of the San Francisco–Oakland Bay Bridge.

At a cost of 38ドル million^[4] (equivalent to 401ドル.3 million in 2023),a parallel bridge was built just east of the 1927 bridge. The new bridge carried all traffic for a few months after it opened in November 1958, then after new ramps were built, the three-lane 1927 span, originally two-way, served westbound traffic while the four-lane 1958 span handled eastbound traffic.

At a cost of 240ドル million (equivalent to 397ドル.51 million in 2023) a new suspension bridge was built, to the west of the two earlier bridges, by the joint venture consisting of Flatiron Structures of Longmont, Colorado, FCI Constructors of Benicia, California, and the Cleveland Bridge & Engineering Company of Darlington, England.^{[4] [5]}

This new bridge was named the Alfred Zampa Memorial Bridge, after an ironworker who worked on a number of the San Francisco Bay Area bridges, including the Golden Gate Bridge, and the original 1927 Carquinez span. The bridge was dedicated on November 8, 2003, and opened for traffic on November 11, 2003. Originally, the plan was to dedicate the bridge on November 15, but complications involving then just-recalled Governor Gray Davis and the transfer of power to Arnold Schwarzenegger resulted in the date being moved. The coins minted to commemorate the event have the original date on them.^[6]

The new suspension bridge, consists of the south anchorage, a transition pier, the South and North towers, and the north anchorage. It has spans of 147 m, 728 m, and 181 m. for a total span of 0.66 miles (1,060 m). It features a pedestrian and bicycle path, part of a bike trail which it is hoped will eventually circle the entire Bay Area. The towers are each founded on two footings, which are each supported by six vertical, 3-metre-diameter (9.8 ft) steel shells infilled with reinforced concrete, followed by 2.7-metre-diameter (8.9 ft) drilled shafts in rock, i.e., cast-in-drilled hole, or CIDH, piles. The total length of the CIDH pile at the South Tower is approximately 89 m, with about 43 m of drilled shaft in rock. The total length of the CIDH pile at the North Tower ranges from 49 to 64 m, with about 16 to 26 m of drilled shaft in rock. The design parameters used for the South Tower piles were later confirmed by a pile load test. Additional field investigations during construction revealed significant variations in rock conditions at the North Tower, resulting in the redesign of the length of the piles. Major construction challenges encountered during construction of the South Tower piles, and the revised construction procedure, i.e., under-reaming, used by the constructor to mitigate caving.

Materials for the New Bridge came from all over the world:

• Steel Caissons for CIDH: XKT Engineering – Vallejo, California
• Orthotropic Deck Sections: IHI – Japan
• Tower and Splay Saddles:
  • Castings: Sheffield Steel – England
  • Finishing and Machining: Kvaerner – England
• Main Cable Wire: Bridon – England
• Wire for Cable Wrapping: Canada
• Cable Bands: France
• Suspenders (Hardware, Casting, Fabrication): WRCA – St. Joseph, Missouri
• (3) Maintenance Travelers Under Deck Sections: Jesse Engineering – Tacoma, Washington

Tolls are only collected from eastbound traffic after they cross from Crockett at the toll plaza on the Vallejo side of the bridge. Although the 2003 Alfred Zampa Memorial Bridge is the newer span, no toll is charged in that direction, continuing the practice of the now-demolished 1927 span. All-electronic tolling has been in effect since 2020, and drivers may either pay using the FasTrak electronic toll collection device or using the license plate tolling program. It remains not truly an open road tolling system until the remaining unused toll booths are removed, forcing drivers to slow substantially from freeway speeds while passing through. Effective January 1 – December 31, 2025 (2025年01月01日 – 2025年12月31日), the toll rate for passenger cars is 8ドル. During peak traffic hours on weekdays between 5:00 am and 10:00 am, and between 3:00 pm and 7:00 pm, carpool vehicles carrying three or more people, clean air vehicles, or motorcycles may pay a discounted toll of 4ドル if they have FasTrak and use the designated carpool lane. Drivers without Fastrak or a license plate account must open and pay via a "short term" account within 48 hours after crossing the bridge or they will be sent an invoice of the unpaid toll. No additional toll violation penalty will be assessed if the invoice is paid within 21 days.^{[7] [8] [9]}

Crossing the original 1927 bridge required a toll, but tolls were removed within five years after the state bought the bridge in 1940. Tolls in 1926 were originally set at 0ドル.60 per car (equivalent to 10ドル.33 in 2023) plus 0ドル.10 per passenger (equivalent to 1ドル.72 in 2023). This was reduced in 1938 to 0ドル.45 per car (equivalent to 9ドル.74 in 2023) plus 0ドル.05 per passenger (equivalent to 1ドル.08 in 2023). After the state took ownership in 1940, tolls were immediately reduced to 0ドル.30 per car (equivalent to 6ドル.52 in 2023). In 1942, tolls were further reduced to 0ドル.25 (equivalent to 4ドル.66 in 2023) before being removed in 1945. Tolls were reinstated in 1958 with the completion of the parallel span, set again at 0ドル.25 (equivalent to 2ドル.64 in 2023). It was increased to 0ドル.35 in 1970 (equivalent to 2ドル.75 in 2023), and then 0ドル.40 in 1978 (equivalent to 1ドル.87 in 2023).^[10]

The basic toll (for automobiles) on the seven state-owned bridges, including the Carquinez Bridge, was standardized to 1ドル by Regional Measure 1, approved by Bay Area voters in 1988 (equivalent to 2ドル.58 in 2023).^[11] A 1ドル seismic retrofit surcharge was added in 1998 by the state legislature, increasing the toll to 2ドル (equivalent to 3ドル.74 in 2023), originally for eight years, but since then extended to December 2037 (AB1171, October 2001).^[12] On March 2, 2004, voters approved Regional Measure 2 to fund various transportation improvement projects, raising the toll by another dollar to 3ドル (equivalent to 4ドル.84 in 2023). An additional dollar was added to the toll starting January 1, 2007, to cover cost overruns on the eastern span replacement of the Bay Bridge, increasing the toll to 4ドル (equivalent to 5ドル.88 in 2023).^[13]

The Metropolitan Transportation Commission, a regional transportation agency, in its capacity as the Bay Area Toll Authority, administers RM1 and RM2 funds, a significant portion of which are allocated to public transit capital improvements and operating subsidies in the transportation corridors served by the bridges. Caltrans administers the "second dollar" seismic surcharge, and receives some of the MTC-administered funds to perform other maintenance work on the bridges. The Bay Area Toll Authority is made up of appointed officials put in place by various city and county governments, and is not subject to direct voter oversight.^[14]

Due to further funding shortages for seismic retrofit projects, the Bay Area Toll Authority again raised tolls on all seven of the state-owned bridges in July 2010. The toll rate for autos on the Carquinez Bridge was thus increased to 5ドル (equivalent to 6ドル.99 in 2023).^[15]

In June 2018, Bay Area voters approved Regional Measure 3 to further raise the tolls on all seven of the state-owned bridges to fund 4ドル.5 billion worth of transportation improvements in the area.^{[16] [17]} Under the passed measure, the toll rate for autos on the Carquinez Bridge was increased to 6ドル on January 1, 2019; to 7ドル on January 1, 2022; and then to 8ドル on January 1, 2025.^[18]

In September 2019, the MTC approved a 4ドル million plan to eliminate toll takers and convert all seven of the state-owned bridges to all-electronic tolling, citing that 80 percent of drivers are now using FasTrak and the change would improve traffic flow.^[19] On March 20, 2020, accelerated by the COVID-19 pandemic, all-electronic tolling was placed in effect for all seven state-owned toll bridges.^[20] The MTC then installed new systems at all seven bridges to make them permanently cashless by the start of 2021.^[21] In April 2022, the Bay Area Toll Authority announced plans to remove all remaining unused toll booths and create an open-road tolling system which functions at highway speeds.^[22]

The Bay Area Toll Authority then approved a plan in December 2024 to implement 50-cent annual toll increases on all seven state-owned bridges between 2026 and 2030 to help pay for bridge maintenance. The standard toll rate for autos will thus rise to 8ドル.50 on January 1, 2026; 9ドル in 2027; 9ドル.50 in 2028; 10ドル in 2029; and then to 10ドル.50 in 2030. And becoming effective in 2027, a 25-cent surcharge will be added to any toll charged to a license plate account, and a 50-cent surcharge added to a toll violation invoice, due to the added cost of processing these payment methods.^{[23] [24]}

• The 1927 span of the Carquinez Bridge is featured on a Season 4 episode of MythBusters in the Miniature Earthquake Machine segment. This experiment, based upon a claim by inventor Nikola Tesla that his mechanical oscillator produced an earthquake in 1898, employed a small tunable reciprocating mass driver to shake the bridge at its resonance frequency. While not structurally significant, the shaking was felt some distance from the driver.
• An hour-length program, titled Break It Down: "Bridge", documenting the demolition of the 1927 bridge aired on National Geographic Channel, on November 1, 2007
• On October 5, 2007, a man jumped off the new 156-foot-high (48 m) bridge. The Coast Guard, Vallejo Police, and Fire responded to find him on the breakwater. He survived the fall.
• Four books have been published about, or featuring, the Carquinez Bridges:Spanning the Carquinez Strait: The Alfred Zampa Memorial Bridge (2003) by Caltrans, and Spanning the Strait: Building the Alfred Zampa Memorial Bridge (2004), Al Zampa and the Bay Area Bridges (2005), and, most recently, Carquinez Bridge: 1927-2007 (2017) all by John V. Robinson.

• The bridge is depicted in the 2017 Netflix TV series 13 Reasons Why .
• The bridge is depicted in the 2016 Czech computer game American Truck Simulator .^[25]

• Benicia–Martinez Bridge
• icon Transport portal
• icon Engineering portal
• flag California portal
• List of bridges documented by the Historic American Engineering Record in California

• Bay Area FasTrak – includes toll information on this and the other Bay Area toll facilities
• Alfred Zampa Memorial Bridge Foundation
• Bridging the Bay History of the Carquinez Bridge, as well as other bridges.
• Caltrans New Carquinez Bridge page
• Building the Al Zampa Bridge – Site written by Dick McCabe Jr, a union ironworker who worked on the bridge with pictures of the construction and a journal of the construction progress.
• Carquinez Strait Bridge (1927) at Structurae
• Carquinez Strait Bridge (1958) at Structurae
• Alfred Zampa Memorial (New Carquinez) Bridge (2003) at Structurae
• [1] Break it Down: "Bridge" on National Geographic Channel.
• [2] Bay Area Toll Authority Bridge Facts on Carquinez Bridge.
• [3] Publisher's Web site for Spanning the Strait: Building the Alfred Zampa Memorial Bridge, John V. Robinson's book about the new bridge.
• Third Carquinez Strait Bridge OAPC Consulting Engineers alternatives and selection report
• Historic American Engineering Record (HAER) No. CA-297, "Carquinez Bridge, Spanning Carquinez Strait at Interstate 80, Vallejo, Solano County, CA", 126 photos, 58 data pages, 8 photo caption pages

• Bridges in the San Francisco Bay Area
• Carquinez Strait
• Bridges in Contra Costa County, California
• Bridges in Solano County, California
• Road bridges in California
• Bridges on the Interstate Highway System
• Interstate 80
• Lincoln Highway
• Steel bridges in the United States
• Suspension bridges in California
• San Francisco Bay
• Toll bridges in California
• Tolled sections of Interstate Highways
• Vallejo, California
• History of Solano County, California
• Bridges completed in 1927
• Bridges completed in 1958
• Bridges completed in 2003
• Historic American Engineering Record in California
• San Francisco Bay Trail
• Cantilever bridges in the United States
• 1927 establishments in California
• U.S. Route 40

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