Bridge Condition
How well are the Bay Area’s bridges maintained?
Bridges define the Bay Area. From the Golden Gate Bridge to the Bay Bridge, they remain iconic symbols of the region, recognizable to people across the world. But they face great threats from natural hazards, as witnessed in 1989 when the Loma Prieta earthquake seriously damaged the Bay Bridge. It is critical to ensure that the region’s bridges are structurally sound so not a single life is lost when the next quake hits. Ongoing investments over the past two decades have profoundly enhanced the condition of hundreds of bridge facilities across the Bay Area.
31%
of Bay Area bridge deck area has been rated as "good” in 2022
11%
of Bay Area bridge deck area has been rated as "poor” in 2022
Regional Performance
Condition of Bay Area bridges have generally improved over the past decades.
Bay Area bridges and overpasses are among those in their best shape since 1992 (the earliest year on record) due to substantial efforts to improve the seismic and structural safety of these critical facilities. The percentage of bridge deck area rated as “poor” hit a peak in 2004 at approximately 40%. Since then, seismic retrofit programs on highway bridges as well as upgrades to elevated freeway structures helped the region reverse that trajectory. As a result, the share of bridge deck area rated “poor” fell by almost 30 percentage points and currently stands at 11% in 2022.
2016
was the region's best year for bridge condition since 1997, with only 7% of the Bay Area’s bridge deck area being rated as “poor”
Historical Trend for Bridge Condition
Local Focus
Most Bay Area counties have seen improved bridge and overpass conditions over the past two decades.
Over the past two decades, many counties in the Bay Area have seen a decrease in their respective share of bridge deck area being rated as “poor.” For example, in Contra Costa County the poor bridge deck area percentage dropped from 46% to 9% between 2002 and 2022. The counties of Alameda, Contra Costa, Marin, Santa Clara, San Francisco, Solano and Sonoma all saw drops in the range of 12 to 47 percentage points during this time period. In San Francisco County, the share of bridge and overpass deck area rated as “poor” is at an all-time recorded low as of 2022. Numerous structural repairs were made during the 2010s and as a result, the share of bridge deck area in San Francisco with a “poor” rating fell from 40% in 2012 to 0.1% in 2022.
However, in more recent years, some counties have experienced a slight uptick in their respective share of bridge deck area rated as “poor.” For example, in Solano County the poor bridge deck area percentage increased from 5% to 15% between 2017 and 2022. The counties of Alameda, Contra Costa, Marin, Napa and Solano all saw increases in the range of 1 to 10 percentage points during this time period.
39%
of bridge and overpass deck area in Alameda County are rated as "good” in 2022, the highest in the Bay Area
35%
of bridge and overpass deck area in San Mateo County are rated as "poor” in 2022, the highest in the Bay Area
Bridge Condition Ratings Map (2022)
National Context
Bay Area has a relatively high share of bridge deck area rated as “poor” compared to other major metro areas in 2022.
Over the past few decades, major metro areas have generally seen improvements in bridge condition. While the Bay Area has made major improvements in bridge condition since the early 2000’s, the Bay Area has 11% of its bridge deck area rated as “poor,” which is relatively high compared to other major metro areas. In 2022, Chicago and New Yok have similar rates of bridge deck area rated as “poor” at 13% and 11%, respectively. Major metros that have low percentages of bridge deck area rated as “poor” include Houston at 1.2% and Atlanta at 0.4% in 2022.
13%
Of bridge and overpass deck area in the Chicago metro area are rated as "poor” in 2022, which is relatively high among large metro areas in the nation
Metro Comparison for Bridge Condition
Sources & Methodology
Bridge deck area rating definitions (Good, Fair, Poor) are from the FHWA Bridge Inventory. Regional performance was examined by summing all of the bridge deck area by rating and dividing it by total bridge deck area. Individual bridges reports 2022 data for bridges within the nine-county Bay Area. For metro comparisons, the Bay Area uses the nine-county region instead of separate metropolitan statistical areas (MSAs). Note that metro comparisons use current MSA boundaries for historical data. In 2018, the FHWA updated its bridge condition metrics, deprecating the terms “Structurally Deficient” and “Structurally Sound” in favor of as "Good", "Fair" and "Poor", which are used in this Vital Signs indicator for current and historical data.