Commonway
Version V. 2026.08.31

Dendritic / Hierarchical

NET-DEN-02
Situational / Discouraged Network

Dendritic / Hierarchical

A tree-like network topology where local streets feed into collectors, which feed into arterials, minimizing through-connections at lower tiers and concentrating traffic onto a smaller number of higher-order routes. Historically progressed through increasingly branch-heavy, cul-de-sac-dominated forms over the 20th century, documented as an internal four-stage spectrum: Fragmented Parallel (c. 1950), Warped Parallel (c. 1960), Loops and Lollipops (c. 1970), and Lollipops on a Stick (c. 1980).

Working assessment: this pattern’s status reflects a preliminary Commonway System judgment call, pending final review.

#Why this pattern exists

Dendritic/Hierarchical networks reduce through-traffic on local streets by design, which is genuinely valuable for neighborhood quiet and safety, but the same branching structure that filters traffic also reduces route choice and increases circuity for everyone, including people walking and biking. This pattern documents both the topology and its historical sub-stages together, since the four named stages are not separate topologies but points along one continuous progression toward heavier branching and fewer through-connections.12

#Key considerations

  • The four historical sub-stages (Fragmented Parallel, Warped Parallel, Loops and Lollipops, Lollipops on a Stick) represent increasing degrees of branching and decreasing route choice, not four separate patterns; later stages have progressively fewer access points, intersections, and lineal feet of street per unit area
  • Pedestrian and bicycle cut-throughs at cul-de-sac heads meaningfully mitigate the circuity penalty for people not in cars, and should be a standard companion treatment rather than an afterthought
  • Independent research has found residents of tree-like/dendritic networks drive measurably more than residents of grid networks, a consideration worth weighing against the traffic-reduction benefit this pattern provides

Grid (NET-GRD-01) (contrasting topology); Superblock/Cellular (a Grid (NET-GRD-01) modifier addressing a similar through-traffic concern by a different mechanism); Marshall’s D-type/Distributory

#References

  1. Precedent-based Southworth, Michael, and Eran Ben-Joseph. Streets and the Shaping of Towns and Cities. Rev. ed. Washington, DC: Island Press, 2003. Chapter 5, "Streets for Living," pp. 105-107. Print/ebook source, no persistent URL to monitor.
  2. Precedent-based Marshall, Stephen. Streets and Patterns. London: Spon Press, 2005. Chapter 4, "Pattern Type," "Developing Typologies of Pattern" (ABCD typology, D-type/Distributory), pp. 83-96. Print/ebook source, no persistent URL to monitor.

Suggest changes to this page (opens in new tab) Last updated August 31, 2026