Street-network Sprawl in Norwich, United Kingdom

What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

To see the state of street-network sprawl across the globe, visit the sprawlmap.

Norwich: city in England, United Kingdom

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Norwich, United Kingdom on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Norwich as of 2014, the overall level of street-network sprawl is 3.52, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.45, 4.55, 3.94 and 3.33. Street construction in Norwich increased in disconnectivity initially but has since improved. The streets constructed in 1976-1990 were the most disconnected.

Quantity of street network construction: The street network in Norwich spans a total of 635 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 3.45, which is highly disconnected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 3.45, 3.52, 3.52 and 3.52. The aggregate street network in Norwich increased in disconnectivity initially,but the trend has turned around after 2000.

Norwich and England do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Norwich peaked in 1976-1990, while the SNDi of street constructions in England peaked in 1991-2000.

How do development practices in Norwich fare in comparison to others in England? Most recently in 2001-2014, street construction in Norwich was the 88th-most disconnected out of the 117 cities in England. Its position in the ranks since 1975 has fallen; relative to other cities in England, street construction in Norwich has become more connected. Norwich ranked 73rd in 1975, 93rd in 1976-1990, 93rd in 1991-2000 and 88th in 2001-2014.

Norwich and United Kingdom do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Norwich peaked in 1976-1990, while the SNDi of street constructions in United Kingdom peaked in 1991-2000.

How do development practices in Norwich fare in comparison to others in United Kingdom? Most recently in 2001-2014, street construction in Norwich was the 104th-most disconnected out of the 138 cities in United Kingdom. Its position in the ranks since 1975 has fallen; relative to other cities in United Kingdom, street construction in Norwich has become more connected. Norwich ranked 88th in 1975, 111th in 1976-1990, 110th in 1991-2000 and 104th in 2001-2014.

Norwich and England follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1991-2000.

To date, Norwich is the 79th-most disconnected out of the 117 cities in England. Its position in the ranks since 1975 has fallen; relative to other cities in England, the street network in Norwich has become more connected. Norwich ranked 73rd in 1975, 79th in 1976-1990, 79th in 1991-2000 and 79th in 2001-2014.

Norwich and United Kingdom follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1991-2000.

To date, Norwich is the 94th-most disconnected out of the 138 cities in United Kingdom. Its position in the ranks since 1975 has fallen; relative to other cities in United Kingdom, the street network in Norwich has become more connected. Norwich ranked 88th in 1975, 94th in 1976-1990, 94th in 1991-2000 and 94th in 2001-2014.

As of 2015, Norwich had a built-up area of 32.27 square kilometers, and a population of 181040 people.

These are some other cities with approximately the same population: