Portland in context: Street-network sprawl trends

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Portland plotted against Maine and United States. While Maine and United States both peaked in 1991-2005, Portland's new street additions peaked in 1991-2005. Most recently, Portland's incremental SNDi fell from 5.64 to 4.52 between 1991-2005 and 2006-2020. In terms of the aggregate network, Portland ranked 1st out of 1 cities in Maine as of 2020.

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

What about similarly populated cities?

• Liangcheng, China
• Jendouba, Tunisia
• Arpora, India
• Dungun, Malaysia
• Karakash, China
• Dhanauji, India

In new street additions, Portland built increasingly disconnected streets from 1975 through 1991-2005, then improved, while Liangcheng built increasingly connected streets from 1975 through 1976-1990, then shifted to more disconnected patterns and Dungun built increasingly disconnected streets over time. For the full network, Portland and Dungun both became progressively more disconnected, while Liangcheng became more connected from 1975 through 1976-1990, then grew more sprawly from 1976-1990 onwards. Portland and Dungun have been growing further apart in their street-network character since 1975.