Tsuyama in context: Street-network sprawl trends

Tsuyama in context

22.42.83.2<19751976–19901991–20052006–2020SNDi of street additions
22.42.83.2<19751976–19901991–20052006–2020SNDi of entire street network
TsuyamaOkayama (Region)Japan (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Tsuyama plotted against Okayama and Japan. The SNDi of new construction in Tsuyama peaked in 1976-1990, compared to Okayama which followed a zig-zag trend with an overall increase and Japan which followed a zig-zag trend with an overall increase. Most recently, Tsuyama's incremental SNDi fell from 3.01 to 2.96 between 1991-2005 and 2006-2020. In terms of the aggregate network, Tsuyama ranked 1st out of 2 cities in Okayama and 95th out of 135 in Japan as of 2020.

New Street Additions (2006–2020)

SNDi value
2.96
Rank in Japan
86th of 135
Rank in Okayama
1st of 2

Entire Network (Aggregate)

SNDi value
2.57
Rank in Japan
95th of 135
Rank in Okayama
1st of 2

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

What about similarly populated cities?

2468<19751976–19901991–20052006–2020SNDi of street additions
2468<19751976–19901991–20052006–2020SNDi of entire street network
TsuyamaGueckedouLala

In new street additions, Tsuyama built increasingly disconnected streets from 1975 through 1976-1990, then improved, while Guéckédou fluctuated in its street-construction patterns and Lala built increasingly disconnected streets from 1975 through 1991-2005, then improved. For the full street network, though, all three cities follow the same trend. Tsuyama and Guéckédou have been growing further apart in their street-network character since 1975.