First things first


Saturday, 16 January 2010

Greener Streets proposal by TW's Barbara Morris

Greener Streets – a proposal for a new approach to street design
in an urban transition area (shortened text*)
Barbara Morris
January 2010

The streets where we live and work form the landscape and the soundscape of our lives. Many town and city dwellers rarely leave this urban landscape, and it’s nature and quality has a profound effect on people’s physical and mental health, and on people’s lifestyle choices. Yet the principles on which most residential streets are designed and managed are still mainly concerned with providing mains services, traffic space and pavements while keeping down the maintenance costs. The result can be streetscapes with poor social space and environmental quality. A new approach to the design of residential streets in towns and cities would now be timely, to see how these everyday, ubiquitous spaces could be re-tuned to match our 21st century needs – both to minimise global warming and to accommodate growing numbers of people happily, safely and healthily in an urban landscape.

Reducing the area covered in paving, concrete and tarmac, and replacing it with areas of soil planted with grass, shrubs and trees will help to minimise the effects of climate change. It can do this by increasing moisture levels in the soil and air during hot, dry periods; by reducing rainwater run-off flowing into storm drains in times of heavy rainfall; and by increasing carbon retention in the soil. A greener street environment can promote bio-diversity, by providing more natural habitats for insects and birds. It also provides a more pleasant environment for its human inhabitants, offering shade on hot days, shelter on windy days, and natural colour and variety all year round.

Greener streets encourages a wider range of people to walk more and can contribute to making the streets an effective social space, where people of all ages mix and meet. The additional surveillance makes people feel safer, for instance on dark evenings. With slower traffic speeds, and more surveillance from passing pedestrians, play spaces for children might even be included in the street layout. This would help to meet the current need for more opportunities for children and teenagers to get out more and take more exercise.

Five step to greener streets
As a starting point, and at a local scale within a Transition Area, the following five steps towards greener streets might be considered:
1. Reinstate roadside verges, or equivalent green spaces, and plant more street trees and shrubs
2. Reinstate garden spaces around houses and flats: and around shops
Encourage residents and landlords to reduce or remove hard-standing (put in place for parking) from garden areas in front of houses, around blocks of flats and around garage courts, and to reinstate topsoil and plants. Replacement surfaces include gravel, grid-blocks, and paved wheel tracks with soft surfaces between. Landlords and local businesses might also be encouraged to create new green spaces in garage and parking areas around flats and shops. And whenever a parking area needs resurfacing, a porous surface might be installed, replacing impervious tarmac or concrete.
3. Permit more on-street parking and reduce speed limit to 20 mph
Reduce the speed limit to 20 mph in all residential streets and return to the normal, non- controlled parking zone conditions, where residents may park in the street across the dropped curbs leading to their own access; also increase the marked parking bays to include all safe parking areas, regardless of length, and reduce where safe the long sight-lines specified for cross-overs (not road junctions). Increasing the area of on-street parking will tend to reduce road width for through traffic. If parking areas are marked out with a change of road surface (perhaps a porous surface), this may convey to road users that these streets are designed to accommodate pedestrians on an equal footing with motor traffic, which can encourage drivers to drive more slowly and more carefully.
4. Redesign the street layout, rather than the current ‘one-design fits all’ approach.
In the longer term, redesign the street layout with more space for greenery, and more space for people to walk and play. Perhaps single lane traffic with passing places instead of the current two lanes: or two-lane traffic with narrower lanes plus passing places for wider vehicles. Some echelon parking could be introduced along the wider streets, interspersed with planting and seats. Street layouts tailored to specific streets might be considered, while still providing space for all the essential services. Where surfaces are needed for walking, cycling or parking, replace the traditional hard, impervious surfaces (tarmac, paving, concrete) with appropriate porous surfaces which would allow rainwater to stay in the local area, rather than being carried away via storm drains. Where appropriate, storm drains could be laid with porous pipework to provide underground irrigation for street trees and reduce run-off surges.
Creating and maintaining a greener street environment needs a significant investment in time, skills, materials, equipment and labour. In the Transition Westcombe Area, some residents may be willing to take on some of this commitment. Where further resources are needed, and in the long term, a greener street environment has the virtue of providing training and employment opportunities in a range of skills Creating a better environment for walking promotes social networking and social inclusion, by making the local area more accessible to more people on foot – a free and healthy way to make local journeys.
5. Explore the future possibilities for designing in energy-saving and energy-creating elements about keeping up-to-date with new technologies as soon as they become practical, such as easier access to mains services or solar cells in street furniture;

The Westcombe Park area
Some of these five steps might combine well with Transition Westcombe’s plans to identify under-used outdoor space suitable for new planting, with the involvement of residents in the planting, care and maintenance of these new green areas in the streets. The Transition Westcombe is a particular place with some local needs and a great deal of local potential. This project proposes to tap local resources, and find local solutions to meet specific situations. The area has a stable, socially-mixed and age-mixed community, with a low turnover compared to some areas of London. There is a mix of low-density housing, mainly built between 1860 and 1940, now often divided into flats: plus numerous blocks of flats built from about 1950 onwards. Development continues in the area, with individual houses and blocks of flats still being built as infill or redevelopment. The area would benefit from new green spaces to counteract the environmental effects of continuing development.
Several streets in the area have wide roadways, with comparatively low levels of traffic. This may offer scope for a reassignment of street-space. Many streets in the area are sought out by walkers and cyclists, as safe and pleasant routes for local journeys. Situated on a north-facing hillside, many streets have good views across the Thames to north London and beyond. From the top of the hillside down to the spring-line, the ground is made up of sandy and pebbly soils. This offers a cost-effective, natural porous surface suitable for walking, playing and parking cars, which also supports green ground-over plants. On this soil, even car parking areas can support ground-cover plants. Below the spring line, the soil is clay, which will support a wider range of trees and shrubs.

What to aim for ?
It has been suggested that “a 10% increase in the green cover in London would offset the enhanced heat-island effect for the next 100 years” . This seems the least we should aim for, and it suggests a minimum, short-term aim of a ten per cent increase within, say, ten years across London as a whole. In a Transition area, a valid short-term aim might be 10 per cent by 2015, with a view to a 20 per cent increase in green cover by 2020. To this could be added any gains made by changing other areas from hard to porous surfaces (without green cover).
*For the full text of the proposal, please email


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