Boston in context: Street-network sprawl trends

Boston in context

23456<19751976–19901991–20052006–2020SNDi of street additions
23456<19751976–19901991–20052006–2020SNDi of entire street network
BostonMassachusetts (Region)United States (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Boston plotted against Massachusetts and United States. While Massachusetts and United States both peaked in 1991-2005, Boston's new street additions peaked in 1991-2005. Most recently, Boston's incremental SNDi fell from 4.11 to 3.27 between 1991-2005 and 2006-2020. In terms of the aggregate network, Boston ranked 3rd out of 10 cities in Massachusetts and 81st out of 333 in United States as of 2020.

New Street Additions (2006–2020)

SNDi value
3.27
Rank in United States
63rd of 333
Rank in Massachusetts
3rd of 10

Entire Network (Aggregate)

SNDi value
2.45
Rank in United States
81st of 333
Rank in Massachusetts
3rd of 10

Rankings go from most connected to most disconnected — rank 1 is the most connected.

What about similarly populated cities?

234567<19751976–19901991–20052006–2020SNDi of street additions
234567<19751976–19901991–20052006–2020SNDi of entire street network
BostonPort HarcourtSan Salvador

In new street additions, Boston built increasingly disconnected streets from 1975 through 1991-2005, then improved, while Port Harcourt fluctuated in its street-construction patterns and San Salvador built increasingly disconnected streets over time. For the full street network, though, all three cities follow the same trend. Boston and San Salvador have been growing further apart in their street-network character since 1975.