Major urban road patterns

Urban road patterns are the arrangements of streets and arterials that form the road network of a city. The common patterns are listed below.

1. Rectangular (grid-iron or block) pattern

  |   |   |   |   |
--+---+---+---+---+--
  |   |   |   |   |
--+---+---+---+---+--
  |   |   |   |   |

• Roads cross at right angles, forming rectangular blocks.
• Advantages: simple, easy land subdivision and direction finding, many alternative routes.
• Disadvantages: many 4-way junctions (more conflicts), long travel between diagonal points, monotonous. Example: Chandigarh.

2. Radial (star and block) pattern

      \   |   /
       \  |  /
   ----- (CBD) -----
       /  |  \
      /   |   \

• Roads radiate from the central business district (CBD), with the areas between them divided into blocks.
• Advantage: direct access to the centre. Disadvantage: traffic congests at the centre, and the radial arms are poorly connected to each other.

3. Radial-circular (ring-radial, star and circular) pattern

        ___________
      /   _______   \
     /   /  \ /  \   \
    |   |--- O ---|   |
     \   \__/ \__/   /
      \_____________/

• Radial roads plus one or more concentric ring roads. The ring roads divert through traffic away from the centre. Example: Delhi, Kathmandu Ring Road.

4. Radial-grid (star and grid) pattern

• Radial roads from the centre are combined with a grid of streets between them; gives direct routes to the centre and easy subdivision of land.

5. Radial-web (spider-web) pattern

• Radials linked by circumferential roads of polygon shape; similar to ring-radial but with direct links.

6. Hexagonal pattern

• Roads form hexagons, with only three-way junctions at 120 degrees; this reduces conflict points, but travel distances are longer and the layout is difficult to set out.

7. Minimum travel pattern

• The city centre is surrounded by sector centres and suburban centres linked by ring and radial roads, laid out so that the total travel between them is a minimum.

8. Linear (ribbon) pattern

• The city grows along a main road or river (e.g. along a highway); simple, but the main road becomes overloaded.

9. Irregular (organic) pattern

• A mixed pattern that develops over time with the terrain (typical of old Nepali towns like Bhaktapur and Patan).