Pisa in context: Street-network sprawl trends

Pisa in context

2.433.64.2<19751976–19901991–20052006–2020SNDi of street additions
2.433.64.2<19751976–19901991–20052006–2020SNDi of entire street network
PisaToscana (Region)Italy (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Pisa plotted against Toscana and Italy. The SNDi of new construction in Pisa followed a zig-zag trend with an overall increase, compared to Toscana which peaked in 1976-1990 and Italy which peaked in 1991-2005. Most recently, Pisa's incremental SNDi rose from 2.38 to 3.22 between 1991-2005 and 2006-2020. In terms of the aggregate network, Pisa ranked 3rd out of 7 cities in Toscana and 23rd out of 88 in Italy as of 2020.

New Street Additions (2006–2020)

SNDi value
3.22
Rank in Italy
35th of 88
Rank in Toscana
5th of 7

Entire Network (Aggregate)

SNDi value
2.31
Rank in Italy
23rd of 88
Rank in Toscana
3rd of 7

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
PisaZirbiWarburton

In new street additions, Pisa fluctuated in its street-construction patterns, while Zirbi built increasingly disconnected streets over time and Warburton built increasingly disconnected streets from 1975 through 1976-1990, then improved. For the full network, Pisa and Zirbi both became progressively more disconnected, while Warburton grew more disconnected from 1975 through 1991-2005, then improved. Pisa and Zirbi have been growing further apart in their street-network character since 1975.