Rennes in context: Street-network sprawl trends

Rennes in context

2.12.83.54.2<19751976–19901991–20052006–2020SNDi of street additions
2.12.83.54.2<19751976–19901991–20052006–2020SNDi of entire street network
RennesBretagne (Region)France (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Rennes plotted against Bretagne and France. The SNDi of new construction in Rennes followed a zig-zag trend with an overall increase, compared to Bretagne which peaked in 1991-2005 and France which peaked in 1991-2005. Most recently, Rennes's incremental SNDi rose from 2.06 to 2.22 between 1991-2005 and 2006-2020. In terms of the aggregate network, Rennes ranked 1st out of 4 cities in Bretagne and 3rd out of 73 in France as of 2020.

New Street Additions (2006–2020)

SNDi value
2.22
Rank in France
6th of 73
Rank in Bretagne
1st of 4

Entire Network (Aggregate)

SNDi value
1.87
Rank in France
3rd of 73
Rank in Bretagne
1st 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
RennesRivneWuzhong

In new street additions, Rennes and Wuzhong both fluctuated in its street-construction patterns, while Rivne built increasingly disconnected streets over time. For the full street network, though, all three cities follow the same trend. Rennes and Wuzhong have been converging in their street-network character since 1975.