Harrisburg in context: Street-network sprawl trends

Harrisburg in context

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

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Harrisburg plotted against Pennsylvania and United States. The SNDi of new construction in Harrisburg rose steadily, compared to Pennsylvania which rose steadily and United States which peaked in 1991-2005. Most recently, Harrisburg's incremental SNDi rose from 3.45 to 5.06 between 1991-2005 and 2006-2020. In terms of the aggregate network, Harrisburg ranked 9th out of 16 cities in Pennsylvania and 51st out of 333 in United States as of 2020.

New Street Additions (2006–2020)

SNDi value
5.06
Rank in United States
263rd of 333
Rank in Pennsylvania
11th of 16

Entire Network (Aggregate)

SNDi value
2.14
Rank in United States
51st of 333
Rank in Pennsylvania
9th of 16

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
HarrisburgSao SebastiaoWeston-super-Mare

In new street additions, Harrisburg built increasingly disconnected streets over time, while São Sebastião fluctuated in its street-construction patterns and Weston-super-Mare built increasingly disconnected streets from 1975 through 1976-1990, then improved. For the full network, Harrisburg and Weston-super-Mare both became progressively more disconnected, while São Sebastião fluctuated in connectivity. Harrisburg and São Sebastião have been converging in their street-network character since 1975.