Ann Arbor in context: Street-network sprawl trends

Ann Arbor in context

2.43.244.8<19751976–19901991–20052006–2020SNDi of street additions
2.43.244.8<19751976–19901991–20052006–2020SNDi of entire street network
Ann ArborMichigan (Region)United States (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Ann Arbor plotted against Michigan and United States. The SNDi of new construction in Ann Arbor followed a zig-zag trend with an overall increase, compared to Michigan which rose steadily and United States which peaked in 1991-2005. Most recently, Ann Arbor's incremental SNDi rose from 2.8 to 3.24 between 1991-2005 and 2006-2020. In terms of the aggregate network, Ann Arbor ranked 5th out of 7 cities in Michigan and 89th out of 333 in United States as of 2020.

New Street Additions (2006–2020)

SNDi value
3.24
Rank in United States
61st of 333
Rank in Michigan
2nd of 7

Entire Network (Aggregate)

SNDi value
2.55
Rank in United States
89th of 333
Rank in Michigan
5th of 7

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

What about similarly populated cities?

2345<19751976–19901991–20052006–2020SNDi of street additions
2345<19751976–19901991–20052006–2020SNDi of entire street network
Ann ArborSt. John'sIdar

In new street additions, Ann Arbor fluctuated in its street-construction patterns, while St. John's built increasingly disconnected streets over time and Idar built increasingly disconnected streets from 1975 through 1976-1990, then improved. For the full network, Ann Arbor and St. John's both became progressively more disconnected, while Idar grew more disconnected from 1975 through 1991-2005, then improved. Ann Arbor and Idar have been converging in their street-network character since 1975.