Nantes in context: Street-network sprawl trends

Nantes in context

2.83.23.64<19751976–19901991–20052006–2020SNDi of street additions
2.83.23.64<19751976–19901991–20052006–2020SNDi of entire street network
NantesPays de la Loire (Region)France (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Nantes plotted against Pays de la Loire and France. The SNDi of new construction in Nantes peaked in 1976-1990, compared to Pays de la Loire which peaked in 1991-2005 and France which peaked in 1991-2005. Most recently, Nantes's incremental SNDi fell from 3.17 to 2.78 between 1991-2005 and 2006-2020. In terms of the aggregate network, Nantes ranked 4th out of 4 cities in Pays de la Loire and 53rd out of 73 in France as of 2020.

New Street Additions (2006–2020)

SNDi value
2.78
Rank in France
19th of 73
Rank in Pays de la Loire
4th of 4

Entire Network (Aggregate)

SNDi value
2.89
Rank in France
53rd of 73
Rank in Pays de la Loire
4th of 4

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

What about similarly populated cities?

1.42.12.83.5<19751976–19901991–20052006–2020SNDi of street additions
1.42.12.83.5<19751976–19901991–20052006–2020SNDi of entire street network
NantesKaminaKikwit

In new street additions, Nantes built increasingly disconnected streets from 1975 through 1976-1990, then improved, while Kamina built increasingly disconnected streets over time and Kikwit fluctuated in its street-construction patterns. Looking at the full network, Kamina and Kikwit both became progressively more disconnected, while Nantes grew more disconnected from 1975 through 1991-2005, then improved. Nantes and Kamina have been converging in their street-network character since 1975.