Boulder in context: Street-network sprawl trends

Boulder in context

2345<19751976–19901991–20052006–2020SNDi of street additions
2345<19751976–19901991–20052006–2020SNDi of entire street network
BoulderColorado (Region)United States (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Boulder plotted against Colorado and United States. The SNDi of new construction in Boulder peaked in 1976-1990, compared to Colorado which peaked in 1991-2005 and United States which peaked in 1991-2005. Most recently, Boulder's incremental SNDi fell from 2.63 to 1.72 between 1991-2005 and 2006-2020. In terms of the aggregate network, Boulder ranked 2nd out of 9 cities in Colorado and 49th out of 333 in United States as of 2020.

New Street Additions (2006–2020)

SNDi value
1.72
Rank in United States
2nd of 333
Rank in Colorado
1st of 9

Entire Network (Aggregate)

SNDi value
2.13
Rank in United States
49th of 333
Rank in Colorado
2nd of 9

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

What about similarly populated cities?

23456<19751976–19901991–20052006–2020SNDi of street additions
23456<19751976–19901991–20052006–2020SNDi of entire street network
BoulderPingyuanBrianka

While Pingyuan and Brianka both fluctuated in its street-construction patterns, Boulder built increasingly disconnected streets from 1975 through 1976-1990, then improved in new street additions. Looking at the full network, Pingyuan and Brianka both fluctuated in connectivity, while Boulder grew more disconnected from 1975 through 1991-2005, then improved.