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
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
– Benicia, California
East at
North atÂ
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
South at
 East End Throwback
East at
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
South atÂ
Interstate 680 south at the original three-wye interchange with I-780 west. 08/23/03
North atÂ
West End
/ Curtola Parkway – Vallejo, California
West at
/ Curtola Parkway
Curtola Parkway East atÂ
East at
West atÂ
West End Throwback
Page updated October 3, 2023.