Aylesbury Vale Area Design Supplementary Planning Document

5.2 Urban structure and sense of place

Figure 5.1: INDICATIVE SITE CONCEPT PLAN 8 - Delivering a clear structure of streets and spaces

Reason

5.2.1 The layout of all existing towns and cities can be simplified into a grid of blocks and plots. The blocks within the grid may be regular shaped squares or rectangles (providing a regular grid), as found in many new towns, or it may be more irregular (providing a more irregular grid), as found in historic towns and villages.

5.2.2 Blocks will vary in size and shape and should be broadly reflective of the sites settlement context whilst respecting natural features, orientation and topography, and providing sufficient back to back distances to provide residential amenity.

5.2.3 In general, blocks between 50 - 120 metres in length provide a permeable network for both pedestrians and vehicles.

(From Left to Right) Figure 5.6: Higher density, urban blocks are suitable in more urban locations Figure 5.7: Lower density, blocks are more suitable in rural locations

Properties expose their rear boundaries to the street providing no animation or overlooking of the streetspace and contrary to secured by design principles

Figure 5.8: New buildings in a street should follow the established building line

Figure 5.9: Perimeter block layout ensuring a clear definition of front and backs and a strong building line to the street; Figure 5.10: Streets should not mix fronts and backs

Left: Figure 5.11: Road dominated: lack of enclosure; Right: Figure 5.12: Place focused: enclosure provided by buildings creates a better street environment

5.2.6 The distance that the building line is set back from the street, together with the height of the buildings determines the level of enclosure that is experienced within the street.

5.2.7 Enclosure may be building dominated or landscape dominated. Trees, hedges and walls can contribute towards creating a sense of enclosure.

5.2.8 Enclosure also creates different conditions. In the case of a square or courtyard, enclosure helps to create a 'static' environment; in a street, where movement is the main characteristic, enclosure helps to create a 'dynamic' environment.

5.2.9 Enclosure is normally calculated by the ratio of the height of the buildings to the width of the street or space.

5.2.10 It is usually appropriate to set buildings back from the public realm to provide a private defensible space. Even the smallest setback can help privacy and security.

5.2.11 The setback distance should normally be between one and three metres with applicants balancing the need for enclosure, site optimisation and privacy. However where larger front gardens are a strong characteristic of an area a greater set back distance may also be appropriate.

5.2.12 Applicants should refer to their Character Study (Chapter 3) to inform the level of enclosure appropriate for their site. As a rough guideline, a ratio of between 1:1.5 to 1:3 (height:width) is likely to be appropriate depending on the hierarchy of street or public space (Refer to Urban Design Compendium). Applicants must seek to maintain or enhance the characteristics of the context within which their site is proposed. The space between buildings should be well defined but not oppressive.

5.2.13 A significant challenge for larger residential developments is to provide a form of development that is appropriate to people rather than cars. When buildings are set back from the street, road space and parking areas should not dominate the street scene.

5.2.14 Human-scaled streets can normally be achieved through increased levels of enclosure (typical of historic developments that pre-date the motor car) by setting buildings close to the street edge (responding to pedestrian rather than car movements).

5.2.15 Creating a sense of enclosure on a main street through a development may require an increase in building height to balance the increased building to building distance.

Reason

5.3.1 Successful communities require a full range of local facilities and services conveniently located and integrated within a settlement and that are connected by safe and pleasant streets.

5.3.2 A mixed-use development helps to support activity and surveillance throughout the day and night contributing to a greater feeling of safety.

Figure 5.14: INDICATIVE SITE CONCEPT PLAN 9 - Provide a mix of uses

  
Left: The Exchange in Aylesbury town centre provides residential uses over restaurants and overlooks a new high quality public space; Right: Local centre at Fairford Leys, Aylesbury provides local services

Figure 5.15: INDICATIVE SITE CONCEPT PLAN 10 Increasing density in relation to accessibility

5.4.3 Within larger urban extensions, including within Aylesbury Garden Town, the character and form of the different parts of the development should vary in order to enhance legibility and sense of place and deliver a variety of residential typologies to create a more balanced community. Refer also to Chapter 7.

5.4.4 This variation of development character across a site will deliver a range of residential densities with higher density development in the more accessible locations and lower density development in the more peripheral areas.

5.4.5 More compact development that creates a stronger sense of street enclosure should be promoted along main streets and around local / neighbourhood centres. This may be delivered through a combination of greater height, vertically articulated frontages and terracing of properties to deliver a more continuous street frontage with underlying rhythm and order. Care must however be given to air quality issues where more compact development prevents air circulating and pollution dispersing effectively.

5.5.1 Landscape features including trees, structures or special buildings can help to add distinctiveness to a place and act as visual cues to aid legibility and understanding.

5.5.2 Streets that create a varied sequence of spaces and vistas aligned with focal buildings can be more rewarding and contribute to the understanding of a place. This can be achieved through:

• A curve or kink in the street;
• Off-setting the street network and terminating the view on a building;
• Creating a pinch point; and/or
• Locating a taller building to terminate an axial view.

Figure 5.16: INDICATIVE SITE CONCEPT PLAN 11 - Enhancing legibility

5.5.3 Buildings marking an important place or location in the townscape may be a little taller than the surrounding context but this increase in height must be proportionate to the role that they play in the streetscape.

5.6.4 Creating roads which naturally reduce traffic speed plays a crucial role in road safety. Traffic calming should form part of the overall street design and should not be achieved through isolated measures like 'speed humps'. Designers should employ good design principles to ensure appropriate traffic speeds. Streets where 'place' functions dominate over 'movement' functions should be designed for a 20 mph speed limit.

5.6.5 Calming measures can help to create a more pedestrian friendly environment and may include:

• Varying the alignment of the vehicular route;
• Use of tight junction radii;
• Narrowing down the carriageway and the use of planting and build outs;
• The provision of designated on-street parking;
• Raised areas at junctions and nodal points; and
• Changes to surface colour/materials.

5.6.6 The use of shared surfaces will not be acceptable on through roads or roads serving more than 25 properties.

5.6.7 Other measures that make a street environment more attractive for pedestrians include:

• Provision of places to stop and rest;
• Areas of shade and shelter;
• Obstruction-free pavement edges to make road crossing easier; and
• Formal crossing points across busier roads, or at high-usage sites such as schools.

5.5.8 Unnecessary road markings, signage and other 'street clutter' should be minimised on streets where 'place' functions dominate over 'movement' functions. This helps to create better places, a better pedestrian environment and encourages safer driving.

Traffic calming measures should be integrated withinthe design of streets

Successful shared surface street (serving local properties only) incorporating tree planting, soft landscaping and parking

Speedbumps as a traffic calming measure for newroads should be avoided.

5.7 Parking

Reason

5.7.1 Applicants should provide parking for both residents and visitors at an adequate level in response to the location of the site. The number of spaces must be determined using the councils parking standards or local standards where these are different (for example as identified within a Neighbourhood Plan).

5.7.2 The accommodation of parking represents a significant design challenge. If poorly designed

parking can have a significant negative impact on the appearance of the public realm.

5.7.3 A balanced approach should be taken to achieve convenient parking in close proximity to households whilst reducing the dominance of parking on the street scene. This will normally result in a range of parking solutions being incorporated. Areas of planting or street trees can help to reduce impacts (refer also to Principle DES35).

5.7.4 Non-allocated, shared parking (generally on street) is more efficient than designating parking to individual dwellings and this approach is encouraged to reduce parking numbers within development schemes especially in respect of terraced housing.

5.7.5 The suitability of parking solutions will vary depending on the location and nature of the proposal.

5.7.6 Parking standards, including the minimum dimensions of parking spaces and garages is set out in VALP Appendix B.

Figure 5.22: A good formal arrangement for a primary street that incorporates parallel parking with regular tree planting within kerb build outs reducing its impact on the street space (Plan)

On street parking

5.7.7 On-street parking for residents provides convenient spaces adjacent to properties and adds to the activity of the street and natural surveillance. On- street car parking also avoids vehicle crossovers on the pedestrian footway.

5.7.8 Lines of on-street parking spaces should be broken up into blocks of a maximum of 5 parking bays separated by kerb build-outs which may accommodate street trees, planting and pedestrian crossings.

5.7.9 Streets must be designed so that where on street parking is proposed there is adequate width to accommodate this parking without causing an obstruction to the highway (refer to VALP Appendix B).

5.7.10 On street parallel parking is a good solution for main streets where it can form part of a formal arrangement that aids legibility of the development. Parking must be designed with particular care to minimise visual impact, enable free movement of buses (where appropriate) and retain continuity of footways.

in marked bays to ensure efficient use of space. Permeable paving is encouraged in these areas.

On plot parking

5.7.12 On plot parking can take a number of forms some of which contribute better to the quality of the street environment.

Within car ports or garages

5.7.13 This solution also allows buildings to be close to the street.Integral garages should be used sparingly as they reduce animation of the street at ground level.

Within undercrofts or basements

5.7.14 Appropriate for apartment schemes. This is generally an acceptable solution provided that a positive interface between the building and street is provided and entrances to car parking areas are designed to minimise intrusion on the street space.

Left: Figure 5.23: Car parking spaces to the side of dwellings reduces the visual impact of cars on the street and allows buildings to be located closer to the back of kerb increasing the sense of enclosure. Right: Figure 5.24: Car parking spaces in front of dwellings results in wider streets and could deliver a streetscape dominated by parking. Planting and co-ordinated boundary treatments can reduce the visual impact

.7.16 Whilst this is historically a popular model it necessitates wider streets, tends to have a considerable visual impact and can restrict informal surveillance of the street space. Parking to the front of dwellings should generally be avoided and where it is proposed its visual impact must be reduced through appropriate boundary treatments and landscape.

Rear parking courts

5.7.17 Applicants should avoid rear parking courts whenever possible. Where they are proposed they should be small scale, overlooked, gated and only serve properties that are located around the court. Entrances to parking courts should be carefully designed to create a semi-private appearance and courts should be secure.

5.8 Design for cyclists

Positive promotion of cycling in Aylesbury town centre

Reason

5.8.1 For cycling to become an attractive alternative to the car a network of attractive, safe and convenient cycling routes must be provided across the area.

5.8.2 It is also important that bicycles are readily accessible and can be securely stored. It is generally recognised that if secure cycle storage is conveniently located within individual dwellings or close to entrances, cycles are more likely to be used. This usually means locating cycle storage close to a buildings entrance at the ground floor level.

5.8.3 The type of storage will depend largely on the type of dwelling and the scale of the development. For houses a flexible storage space could be provided for bins, cycles and other items (e.g. e-scooters). Refer also to Principle DES31.

5.9 Layout of commercial areas and infrastructure

Buildings set within large areas of hardstanding should be avoided. Office building is set back from the street and the entrance is not obvious

Left: Figure 5.28 - Concept for employment area indicating primary route as boulevard, central space and key gateway buildings. Centre: Figure 5.29 - Layout plan showing indicative block layout with frontage and entrances overlooking the boulevard. Right: Figure 5.30 - Service yards and parking should be internalised within the perimeter block to reduce impact on the street environment

5.10 Refuse, storage and utilities

Reason

5.10.1 If not properly planned for refuse collection and storage can have a significant detrimental impact on the quality of the streetscape.

5.10.2 Applicants should refer to the AVDC Recycling and Waste Advice Note for Developers 2019.

5.10.3 In accordance with the recommendations in Manual for Streets residents should not be required to carry waste more than 30m (excluding any vertical distance) to the storage point; waste collection vehicles should be able to get to within 25m of the storage point and the gradient between the two should not exceed 1:12.

Reason

5.10.4 Consideration of the location of refuse storage and utilities apparatus must take place early in the design process as they can have considerable impact on the quality of environment within a development.

5.10.5 Applicants should refer to the AVDC Recycling and Waste Advice Note for Developers 2019. This provides details on the size and capacity of bins for residential and commercial properties and general requirements on their location (refer to para 5.10.2 for the link).

5.11 Open space and public realm

Reason

5.11.1 Open space creates an opportunity to reinforce a sense of place, as well as building stronger cohesion between new and existing settlement. They can be the focus for social interactions, play, recreation, travel and events; they should therefore be multi-functional and central to development.

5.11.2 Spaces should be designed to cater for specific uses designed in anticipation of the type and level of use and activity that may take place within them. Potential changes of use throughout the year should be considered, as well as how people are going to move through the space.

5.11.3 Previous studies into the local context and surrounding character of the site should be drawn upon (Chapter 3) when designing the open space, as well as responding to existing settlement needs. Applicants should refer to the AVDC Assessment of Open Space, Sports and Recreation Needs for Aylesbury Vale (and forthcoming strategies) for the required type and amount of open space and areas for sport, play and recreation.

5.11.4 Long-term management and maintenance of open spaces should be considered at an early stage in the design process.

5.11.13 The multi-functional benefits of trees and vegetation include aesthetic value, visual screening, shelter, recreation, cultural significance, CO2 absorption, cooling properties, pollutant removal, improving air quality, reducing surface run-off and habitat value. Maintenance regimes of trees and vegetation should be relaxed where appropriate to encourage greater structural diversity and increase the number of species niches.

How to use

This table provides a checklist for use by both the applicant and planning officer to check that appropriate consideration has been given to how an application has addressed the site layout, streets and spaces.