Rome in context: Street-network sprawl trends

Rome in context

2.83.54.24.9<19751976–19901991–20052006–2020SNDi of street additions
2.83.54.24.9<19751976–19901991–20052006–2020SNDi of entire street network
RomeLazio (Region)Italy (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Rome plotted against Lazio and Italy. The SNDi of new construction in Rome followed a zig-zag trend with an overall increase, compared to Lazio which rose steadily and Italy which peaked in 1991-2005. Most recently, Rome's incremental SNDi rose from 4.44 to 4.74 between 1991-2005 and 2006-2020. In terms of the aggregate network, Rome ranked 3rd out of 7 cities in Lazio and 57th out of 88 in Italy as of 2020.

New Street Additions (2006–2020)

SNDi value
4.74
Rank in Italy
73rd of 88
Rank in Lazio
6th of 7

Entire Network (Aggregate)

SNDi value
3.13
Rank in Italy
57th of 88
Rank in Lazio
3rd of 7

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

What about similarly populated cities?

3.244.85.6<19751976–19901991–20052006–2020SNDi of street additions
3.244.85.6<19751976–19901991–20052006–2020SNDi of entire street network
RomeManchesterKollam

In new street additions, Rome fluctuated in its street-construction patterns, while Manchester built increasingly disconnected streets from 1975 through 1991-2005, then improved and Kollam built increasingly connected streets from 1975 through 1976-1990, then shifted to more disconnected patterns. For the full network, Rome and Manchester both became progressively more disconnected, while Kollam became more connected from 1975 through 1976-1990, then grew more sprawly from 1976-1990 onwards. Rome and Manchester have been converging in their street-network character since 1975.