4.3 Creating a street network

The choice of street type will largely depend on a street’s position within the wider network, known as ‘arteriality’ [Reference 8]. For example, a primary street must always connect to other primary streets, or the trunk road network; Secondary streets should always connect from primary streets or high streets, and so on.

The type of junction used to connect the different street types is also important, as well as the distances between different street types which defines the urban block. These different rules form a code which can be used to generate street patterns that are functional and legible.

Proposed layouts should not lead to a tree-like, or ‘dendritic’, form of street network as is common in modern suburban development.

Street network permeability and connectivity must be achieved.

Primary Streets - link road (1.a)

• Must connect to either another link road (1.a) or to the trunk road network (motorway, county, etc).
• Can connect to Primary Streets - Avenue (1.b), High Streets - High activity / Arterial (2.a), Secondary streets (3), and Tertiary Streets - Rural lanes (5.c).
• Cannot connect to High Streets - Low traffic (2.b), High Streets - Traffic free (2.c) Local streets (4), Tertiary streets - Shopping mews (5.a), Tertiary streets - Residential mews (5.b).

Primary Streets - Avenue (1.b)

• Can connect to Primary Streets - Link road (1.a), Primary streets - Avenue (1.b), High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Secondary streets (3), Local streets (4), and Tertiary streets - Rural lanes (5.c).
• Cannot connect to Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b).

High Streets - High activity / arterial (2.a)

• Can connect to Primary Streets - Link road (1.a), Primary Streets - Avenue (1.b),High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Secondary streets (3), Local streets (4), Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b).
• Cannot connect to Tertiary streets - Rural lanes (5.c).

High Streets - Low traffic (2.b)

• Can connect to Primary Streets - Avenue (1.b), High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Secondary streets (3), Local streets (4), Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b).
• Cannot connect to Primary Streets - Link road (1.a) and Tertiary streets - Rural lanes (5.c).

High Streets - Traffic free (2.c)

• Can connect to Primary Streets - Avenue (1.b), High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Secondary streets (3), Local streets (4), and Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b) (Only if it has alternative vehicle access from another type of street).
• Cannot connect to Primary Streets - Link road (1.a), and Tertiary streets - Rural lanes (5.c).

Secondary streets (3)

• Must connect to one type of Primary street (1.a) or (1.b), a Local street (4), or another Secondary Street (3).
• Can connect to High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b).
• Cannot connect to Tertiary streets - Rural lanes (5.c).

Local streets (4)

• Must connect to either a Primary Street - Avenue (1.b), a High Street - Arterial (2.a), a Secondary Street (3) or another Local Street (4).
• Can connect to High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Tertiary streets - Shopping mews (5.a) and Tertiary streets - Residential mews (5.b).
• Cannot connect to Primary Streets - Link road (1.a), and Tertiary streets - Rural lanes (5.c).

Tertiary streets - Shopping mews (5.a)

• Must connect to one type of High Street (2.a), (2.b) or (2.c), or a Secondary Street (3), or another Tertiary street - Shopping mews (5.a).
• Can connect to Local streets (4), and Tertiary streets - Residential mews (5.b) (Only if it has alternative vehicle access from another type of street).
• Cannot connect to Primary Streets - Link road (1.a), Primary Streets - Avenue (1.b), and Tertiary streets - Rural lanes (5.c).

Tertiary streets - Residential mews (5.b)

• Can connect to High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c) (Only mews has alternative vehicle access from another type of street), Secondary streets (3), Local streets (4), Tertiary streets - Shopping mews (5.a) (Only if mews has alternative vehicle access from another type of street), and Tertiary streets - Residential mews (5.b).
• Cannot connect to Primary Streets - Link road (1.a), Primary Streets - Avenue (1.b), and Tertiary streets - Rural lanes (5.c).

Tertiary streets - Rural lanes (5.c)

• Can connect to Primary Streets - Link road (1.a), Primary Streets - Avenue (1.b), and Tertiary streets - Rural lanes (5.c).
• Cannot connect to High Streets - Arterial (2.a), High Streets - Low traffic (2.b), High Streets - Traffic free (2.c), Secondary streets (3), Local streets (4), Tertiary streets - Shopping mews (5.a), and Tertiary streets - Residential mews (5.b).

First and foremost, the spacing between junctions, and therefore streets, should be determined by urban design considerations such as permeability, walkability and the need to create blocks that are in keeping with the surrounding context and tie into existing street patterns.

This means junction spacing should be limited, using crossroads and short stagger distances, and keeping block sizes short (ideally between 50m and 150m: see 4.5 below).

On new build developments the distance between junctions should generally be smaller toward the centre in areas of high footfall resulting in junctions at more regular intervals as seen in many historic places, as shown in the examples below.

References

• Reference 8: Marshall, S. (2004) Streets and Patterns (Return to content for reference 8).