Interstate 780 California

Interstate 780 California

Overview

Interstate 780 is a four lane freeway joining the cities of Vallejo and Benicia along a parallel alignment to Carquinez Strait in Solano County. The end of I-780 at Lemon Street ties into Curtola Parkway, a four lane arterial spurring west to California State Route 29 (Sonoma Boulevard) near Downtown Vallejo.

History

The link between I-80/680 was created in 1976,1 when I-680 was rerouted northward from Benicia to Fairfield over the freeway on California State Route 21 to I-80. The freeway mainline dates back to 1962, with the I-80 bridges at the west end built in 1958.

Route Information

  • East End – Benicia, CA

  • West End – Vallejo, CA

  • Mileage – 6.50

  • Cities – Vallejo

  • Junctions – I-80 I-680

Source: December 31, 2021 Interstate Route Log and Finders List

I-780 Annual Average Daily Traffic (AADT)

Source: Caltrans 2017 Traffic Volumes : Route 505-980

 Photo Guides

East End I-680 – Benicia, California

I-780 East at I-680

I-780 east at I-680 - Benicia, CA

I-780 arcs one mile eastward from the diamond interchange (Exit 6) with E Fifth Street in Benicia to Interstate 680 at the north end of the Benicia-Martinez Bridge over the Sacramento/San Joaquin River Delta. 07/17/09

I-780 east at I-680 - Benicia, CA

Eastbound Interstate 780 reaches Exit 7A for I-680 north to Fairfield. This flyover connection was constructed during early stages of the 2001-07 Benicia-Martinez Bridge expansion project. 07/11/18

I-780 east at I-680 - Benicia, CA

Interstate 780 concludes as traffic separates for I-680. Traveling 70.5 miles overall, I-680 encircles the San Francisco Bay area through a number of East Bay Cities south to San Jose. 07/11/18

I-680 North at I-780

I-680/Benicia-Martinez Bridge north at I-780

Constructed between late 2001 and August 2007, the Benicia-Martinez Bridge spans the Sacramento and San Joaquin Delta, which is also known as the Carquinez Straits and Suisun Bay. The concrete segmental bridge accommodates five lanes of northbound traffic for I-680 to the left exit with Interstate 780. 07/05/13

I-680/Benicia-Martinez Bridge north at I-780

The directional T interchange (Exit 58A) linking I-680 and I-780 was rebuilt along with the new Benicia-Martinez Bridge. Left side ramps remained in the design due to area terrain and cost reduction. 03/10/15

I-680/Benicia-Martinez Bridge north at I-780

Crossing into Solano County Interstate 680 makes a gradual descent from the Benicia-Martinez Bridge above Army Point. I-780 branches northwest, with the initial four exits serving the city of Benicia. 03/10/15

I-680 South at I-780

I-680 south at I-780 - Benicia, CA

Interstate 680 crosses a long viaduct above Bayshore Road and industrial areas west Suisun Bay leading to I-780. 07/11/18

I-680 south at I-780 - Benicia, CA

Navigating through an S-curve, I-680 progresses south from Bayshore Road to the directional T interchange (Exit 58) with Interstate 780 west. 07/11/18

I-680 south at I-780 - Benicia, CA

An auxiliary lane opens along I-680 southbound to Exit 58 for I-780. Interstate 780 leads west through Benicia to I-80 at Vallejo; I-680 continues south over the Benicia-Martinez Bridge en route to Concord, Walnut Creek and Danville. 07/11/18

I-680 south at I-780 - Benicia, CA

Leading south toward the George Miller, Jr. Memorial Bridge across Carquinez Strait, the roadways of I-680 separate through the exchange with I-780. The Benicia Bridge Vista Point lies between. 07/11/18

I-780 East End Throwback

I-780 East at I-680

I-780 east at I-680 - 2004

This button copy sign along I-780 east at Fifth Street pre-dated the conversion of SR 21 to I-680 through Benecia, with an outline for I-680 overlaying a shield for the previous state route. This style of overhead sign was common along I-680 prior to its reconstruction through Concord and Walnut Creek in the 1990s. 11/26/04

I-680 South at I-780

I-680 south at I-780 - 2003

Interstate 680 south at the original three-wye interchange with I-780 west. 08/23/03

I-680 North at I-780

I-680 north at I-780 - 2004

Prior to completion of the northbound bridge in 2007, the Benicia-Martinez (George Miller, Jr. Memorial) Bridge built in 1962 carried two-way traffic across Carquinez Straight. 04/02/04

I-680 north at I-780 - 2004

Three lanes of traffic along I-680 north passed through a toll plaza prior to the three-wye interchange with Interstate 780. 04/02/04

I-680 north at I-780 - 2004

The left exit for I-780 departed below the partially built flyover linking I-780 east with I-680 north to Interstate 80 near Cordelia. 04/02/04

West End I-80 / Curtola Parkway – Vallejo, California

I-780 West at I-80 / Curtola Parkway

I-780 west at I-80 - Vallejo, CA

Replaced button copy sign for Interstate 80 at the diamond interchange (Exit 13) with Glen Cove Road. 02/19/12

Interchange sequence sign 0.75 miles ahead of I-80 on I-780 west

Advancing west on Interstate 780, three quarters of a mile ahead of I-80. 07/15/23

I-780 west at Cedar St, a half mile ahead of I-80 east

Substandard ramps connect I-780 west with Cedar Street north just ahead of the cloverleaf interchange with I-80. A weaving traffic pattern ensues between the Cedar Street entrance ramp and Exit 1 B. 07/15/23

I-780 west at Exit 1 B for I-80 east to Sacramento, CA

Exit 1 B parts ways with Interstate 780 west for I-80 leading northeast to Vacaville, Davis and Sacramento. The Laurel Street Bridge spanning the freeway here was replaced between May 2017 and January 2018. 07/15/23

I-780 west at Exit 1 A to I-80 west

Exit 1 A loops onto a c/d roadway lining I-80 west to Lincoln West. Interstate 80 continues southward across the tolled Alfred Zampa Bridge between Vallejo and Crockett. 07/15/23

I-780 west transitions onto Curtola Parkway

Interstate 780 spurs west from Exit 1 A a quarter mile to Lemon Street at Curtola Parkway. 07/15/23

I-780 west at I-80 - Vallejo, CA

Curtola Parkway extends west from Lemon Street to SR 29 south of Downtown Vallejo. The adjacent Curtola Park and Ride facility was relinquished by the state of California in Decemmber 2017.1 03/10/15

Curtola Parkway East at I-780 I-80

Curtola Pkwy east becomes I-780 at I-80.

Curtola Parkway east transitions to Interstate 780 beyond the traffic light at Lemon Street. The freeway quickly meets Exit 1 A for I-80 west to Oakland and San Francisco. 07/15/23

I-780 east at I-80 east

The first sign for Interstate 780 eastbound to Benicia and Martinez precedes the loop ramp at Exit 1 B for I-80 east toward Fairfield and Sacramento. This exchange was formerly the north end of Interstate 680. 07/15/23

I-80 East at I-780

I-80 east at Magazine St, a half mile ahead of I-780

The first of two guide signs along Interstate 80 east for I-780 appears at the compact folded diamond interchange (Exit 29 C) with Lincoln Road east at Magazine Street. 07/15/23

I-80 east at the c/d roadway for I-780 and Curtola Pkwy

A collector distributor roadway (Exit 30 A) separates from the eastbound mainline of I-80 for ramps to Interstate 780 to Benicia, Curtola Parkway west toward Downtown Vallejo and Lincoln Road at Benicia Road. 07/15/23

I-80 West at I-780

I-80 west at I-780 - Vallejo, CA

Passing through a substandard parclo B2 interchange with 14th and Georgia Streets, motorists on Interstate 80 west next approach the c/d roadway (Exit 30A) for I-780 east and Curtola Parkway west. 07/02/13

I-80 west at I-780 - Vallejo, CA

The single lane c/d roadway approaches the westbound off-ramp to Curtola Parkway, the local continuation of I-780 west to SR 29. A loop ramp follows for the freeway east to Benicia and the Benicia-Martinez Bridge (I-680) south to Concord. 07/02/13

I-780 West End Throwback

Curtola Pkwy east at I-780/80 - 2004

The previous button copy signs along Curtola Parkway east at I-780 and I-80 east. 11/26/04

I-780 east at Exit 1 B for I-80 east in 2015

The button copy overheads on I-780 east at Exit 1 B were replaced in kind with reflective signs. 03/10/15

I-780 west at I-80 in 2012

The previous Laurel Street Bridge at Exit 1 B was substandard, not meeting Interstate vertical clearances. 02/19/12

I-80 east at Magazine St and ahead of I-780 in 2009.

Former button copy overheads predating the exit numbering system along I-80 east for Magazine Street and Interstate 780. 07/18/09

I-780 west at I-80 west in 2012

Porcelain enamel overhead for Interstate 80 west at the end of I-780 westbound. 02/19/12

Sources:

  1. California Highways (www.cahighways.org): Route 780.

Page updated October 3, 2023.