Links to the 'connections' and 'custodianship' components of the seven Cs (Urban Design Protocol).
What is connectivity?
Connectivity is the degree to which networks - streets, railways, walking and cycling routes, services and infrastructure - interconnect. Good connections encourage access within a region, city, town or neighbourhood.
Well connected cities, towns and neighbourhoods can:
- enhance land values
- make local shops and facilities more viable
- enhance people's safety and security by encouraging surveillance
- encourage more walking and cycling, leading to health benefits
- reduce vehicle emissions through fewer cars being used for non-work trips.
Overview of the research
Well connected networks enhance access, and give people a choice of routes. But networks need to offer people more than access alone. They must also provide high quality spaces and routes that people find safe and enjoyable to use.
Improving connections and access can have both positive and negative effects. Good transport systems can advantage everyone by supporting economic activity and enhancing land values in particular locations. But they can also create negative effects such as noise and pollution. Urban design can help minimise these costs.
In particular, the accessibility and lack of congestion offered by city fringe locations make these peripheral areas highly attractive to some kinds of businesses. But city fringe development may have adverse effects for the wider city - social isolation in some areas, greater pollution and more traffic congestion. This is where urban design can help - ensuring that the provision of access to the city periphery is carefully managed so it does not undermine the overall form of the city, and a net benefit for the region is achieved.
Good transport connections - both internally, and to other regions and cities - are shown to be a feature of competitive cities, although the exact relationship between transport connectivity and competitiveness is not clear.
One effect of good connections that is abundantly clear across all the literature is that it encourages more physical activity and reduces car dependence. There is compelling evidence about the health benefits of increased physical activity in general, and also about the specific health benefits of walking and cycling - especially if these activities are part of everyday life. Connections that are high quality, visible, safe and offer quick, convenient access to facilities increase the likelihood that people will walk to work or anywhere else. This may even be the case for shopping trips, often thought to be car-dependent.
These 'walkable' environments offer other significant benefits beyond improving people's health. They can reduce the public costs associated with car use, such as traffic congestion and the provision of road and parking facilities. There are also positive economic spin-offs for retailers and employers because of the higher pedestrian traffic.
Safety is also influenced by connectivity. There is evidence of a significantly reduced risk of burglary when areas are well connected and visible, as there is more opportunity for natural surveillance. The same is true for individual buildings: there are fewer burglaries where low walls allow views in and out, 'active edges' face the street, and both cars and pedestrians use the street. These conditions can also help reduce social isolation within neighbourhoods.
To be safe, places must also be well used. For this to happen, good urban design should address connectivity not in isolation, but alongside other qualities such as the mix of activities and land uses.
Poor connectivity and infrastructure limits investment opportunities and "imposes costs which later have to be borne by public and private stakeholders, although original developers have often moved on," according to a 2001 study conducted jointly by the UK's Commission for Architecture and the Built Environment (CABE) and the Department of the Environment, Transport and the Regions (DETR).
Carmona et al, 2001
"Physical inactivity is an important determinant of ill-health, and even moderate levels of activity confer health benefits."
Giles-Corti & Donovan, 2002
A study of residents of Botany Downs, an urban growth area in Manukau where 97 percent of respondents own or have access to a car, found that less than 10 percent go beyond Botany Downs for their day-to-day shopping. Just under half walk to the shops, while 22 percent both walk and drive.
Over 80 percent of respondents reported doing their bulk grocery shopping in Botany Downs as well. More than half drive, 17 percent walk or drive, and 22 percent walk for their bulk shopping.
Thompson-Fawcett & Bond, 2004
"Many ... successful cities also place a high premium upon good internal access and have invested heavily in efficient inter-modal public transport systems."
Parkinson et al, 2004
One American study found rates of walking for shopping trips were 20 percent higher in pedestrian oriented neighbourhoods than those which were car oriented. This goes against conventional wisdom "that consumer shopping is heavily auto oriented".
The same study also found that - while transit trips are more influenced by factors other than neighbourhood design - pedestrian oriented development was correlated with a 20 percent higher share of walking trips to transit stations than auto oriented development.
Cervero & Radisch, 1996
A major study in the UK found that street connectivity is linked with reduced occurrence of burglary. This challenges the view that complex cul-de-sac arrangements lead to increased safety and security.
He found that houses on streets accommodating cars and pedestrians had a burglary rate less than half that of those on pedestrian-only access routes. And on streets with 'active edges', burglary rates were reduced by up to two-thirds.
The value of connectivity
© Ministry for the Environment