8 Percent Of Greater Boston Bridges Structurally Deficient: Report

BOSTON, MA — Eight percent of bridges in the Greater Boston area are considered "structurally deficient," according to a new report from the Massachusetts Budget and Policy Center.

In total, the region has 115 deficient bridges, joining 644 bridges in disrepair across the state and another 218 in “unknown” condition. Greater Boston residents, on average, live 1.2 miles from a structurally deficient bridge, according to the Policy Center report.

The "structurally deficient" label does not mean bridges are necessarily at risk of collapsing. While bridge collapses are “extremely rare,” though, researchers said the impacts of bridge closures or weight restrictions on deteriorating bridges are still topics of concern. Such disruptions can worsen traffic congestion, increase fuel use and slow down the flow of commerce, researchers said.

Greater Boston has seven bridges that are closed and 125 with load or capacity limitations.

Utilizing data from the Massachusetts Department of Transportation (MassDOT), researchers studied the condition of close to 8,000 documented bridges across Massachusetts.

They said the Department of Transportation’s Asset Management Advisory Council recently told the state legislature that Massachusetts “is fourth worst in the nation for the percentage of poor bridges” by area.

Bridges in Massachusetts are deteriorating due to a combination of age and harsh winter weather conditions, according to the Policy Center. On average, a Massachusetts bridge was built or most recently reconstructed 56 years ago, surpassing the national average of 44 years, researchers said.

“Like cars or houses, bridges become more difficult and costly to maintain as they become older,” the report said.

Greater Boston’s structurally deficient bridges range in size and type, with the MassDOT dataset tracking all MassDOT and municipally-owned bridges with spans greater than 20 feet. The set also includes some MassDOT highway and municipal bridges with spans between 4 and 20 feet, although those inventories remain incomplete, according to researchers.

The data excludes bike and pedestrian bridges, federal bridges, bridges owned by other state entities and bridges that are privately owned.

Bridges can earn “structural deficient” status when at least one major weight-bearing component has “serious issues” that require repair or replacement, according to the Policy Center’s report.

Across the state, the Policy Center found that racial and ethnic minorities and limited-English proficient households, on average, live closer to a structurally deficient bridge than others.

Moving forward, the Policy Center said Massachusetts bridges may continue to deteriorate due to combined impacts of flooding and erosion, heavier vehicles and old age unless the state makes more substantial investments in infrastructure maintenance and repair.

Read the full Policy Center report here.