5.7 Junction geometry and characteristics

Junctions must not solely be designed for movement. They are also key places in the street network where people meet and spend time. They can be a focus point, with taller buildings, public spaces, landmark buildings, and local amenities. Junctions between primary streets will generally have greater intensity and opportunities for public interaction. These spaces should be a focus for new developments.

How the buildings look and interact with the junction is of particular importance. They should create a sense of enclosure, have well defined frontages and clear boundaries between public and private space. Opportunities for public space should be encouraged.

Roundabouts

Standard DMRB (Design Manual for Roads and Bridges) roundabouts must not be used in areas of pedestrian activity in towns, villages and urban areas.

They consume vast amounts of space, encourage higher speeds, are a physical and psychological barrier for pedestrians and dangerous for cyclists. In 2018 20% of all cyclist deaths and serious injury in the UK were on roundabouts [Reference 14].

Mini and compact roundabouts, or roundels, are permitted.

Junction design

Minor junction types that are appropriate for residential areas include:

• Crossroads and staggered junctions;
• T and Y junctions;
• Formal and informal squares;
• and Mini and compact roundabouts, roundels.

Junction radii should be as small as possible to ensure that the pedestrian desire line is maintained and that vehicles turn slowly.

It is not necessary to design junctions for large vehicles such as bin lorries that will only use them occasionally.

In most streets, it is acceptable for such vehicles to take up both lanes when turning.

Vehicle tracking software should be used to check swept paths and verify the design.

As well as being less safe for pedestrians and cyclists, large radii junctions result in inefficient land use and should be avoided.

On existing junctions, the radii can be reduced using kerb build outs, providing more space for public realm and furniture, planting and trees, or parking.

On new junctions, buildings should be used to define the junction and create corner buildings. This makes more efficient use of the available space, and provides opportunities for irregular shape building plots, especially on Y junctions, that can add to the character of a development.

In some circumstances, it can be possible to use the reclaimed space on existing junctions for new buildings, especially where it provides an opportunity to restore historic street patterns that have been damaged by previous road schemes.

Overrun areas should be avoided on residential streets but may be required on streets with high volumes of large vehicles.

Figure 5-6: Vehicle tracking a refuse vehicle on tight corners (Credit - Create Streets)

Figure 5-7: Reducing junction radii reduces vehicle speeds and improves pedestrian and cycle safety (Credit – Create Streets)

Figure 5-8a: Reduced kerb radii improves pedestrian crossing and provides additional space for greening. (Credit - Create Streets)

Figure 5-8b: Reduced kerb radii improves pedestrian crossing and provides additional space for greening. (Credit - Create Streets)

Figure 5-9a: Carriageway deflection, sharp corner radii, street trees and changes in material all help reduce speeds in residential streets. L: Poundbury, Dorset. (Credit - Andy Cameron)

Figure 5-9b: Carriageway deflection, sharp corner radii, street trees and changes in material all help reduce speeds in residential streets. Derwenthorpe, York (Credit - Andy Cameron)

References

• Reference 14: Source: Local Transport Note 1/20 Cycle Infrastructure Design Sec 10.7 (Return to content for reference 14).