Layered Networks
Layered Networks
We prioritize and organize different travel modes within constrained rights-of-way to create safe, efficient, and fair transportation systems for all users.
Rooted in complete streets and multimodal design principles, layered networks have become one of the most valuable advances in balancing the needs of all roadway travelers in an overall network. Endorsed by the Transportation Research Board and codified by the Institute of Transportation Engineers, this recommended practice aims to help balance land use contexts and the diverse and competing needs of pedestrians, cyclists, drivers, transit, and freight within constrained rights-of-way. By identifying, prioritizing, and overlaying these modal layers, practitioners can create comprehensive systems that serve everyone’s needs, reduce potential conflicts, and enhance safety and efficiency.
Layered network design creates continuous and connected routes for each mode of travel. By understanding the role each road segment plays in the overall network, practitioners can decide which travel modes to prioritize on which streets. As a result, streets are designed with features that cater to those priorities. Compatible modes, like bikes and pedestrians, can share the same road segments, while conflicting modes, like bikes and transit, would be prioritized on different streets. This strategy helps build well-connected multimodal networks that meet local operational standards and provide safe and equitable access for all without the difficulties of trying to accommodate everyone on every road.
Three Key Principles for Designing Layered Networks
Identify the Primary Modes
Steadfast complete streets design requires first identifying the primary use of a street.
Use a Network Approach
Distinguishing streets with the same primary use helps create continuous, connected routes for each mode of travel. By understanding how each segment fits into the network, planners can prioritize modes and design streets to match those priorities.
Performance Measures Count
Performance measures should sync with the street’s primary use. If it’s a transit-priority street, transit travel time, reliability, and quality of amenities are the most important measures of success.
Tie-Breaking Multiple Modal Priorities
When multiple modal networks overlap, planning for complete streets means balancing limited space. Modal tiers help guide space allocation, but what happens when multiple Tier 1 modes share the same road? Modal prioritization offers a consistent framework: the higher-priority mode gets more space.
As shown in the graphic, prioritization depends on the land use context. For example, walking is prioritized in areas with high pedestrian activity, while driving may take priority in suburban settings. On a main street, a road shared by cars and pedestrians would favor walkers. In a suburban corridor, it would prioritize drivers.
Modal priorities are intended to provide guidance but may vary based on special circumstances, local priorities, and agency directives.
Source: SEMCOG/MDOT Multimodal Tool User Guide
Be sure to explore our SEMCOG/MDOT Multimodal Tool, a time-saving and real-time way to evaluate your layered networks. This first-of-its-kind web application streamlines the design and testing of complete streets and multimodal layouts balancing the various travel modes. By building out street cross-sections, users can instantly evaluate how well the design serves each of the travel modes and its impact on performance measures. For agencies, it offers a strong technical basis to justify how streets are being designed or reconfigured assuring that all modes are receiving priority treatment on their appropriate networks.
Team up with the Fehr & Peers layered network experts to create custom, inclusive plans and designs for your community.
