Classification Categories

The American Walkability Atlas classifies neighborhoods into five intersection density categories to describe how connected neighborhood street networks are. Intersection density measures the concentration of street intersections within a neighborhood and serves as one of the four variables used by the EPA’s National Walkability Index. Higher intersection density generally reflects shorter blocks, multiple travel routes, and greater street connectivity, while lower intersection density often indicates larger blocks, cul-de-sacs, or more automobile-oriented development. Research has consistently identified street connectivity as one of the strongest predictors of walking, bicycling, and overall accessibility (Cervero & Kockelman, 1997; Frank et al., 2005; Ewing & Cervero, 2010).

• Very Low Intersection Density: Neighborhoods with sparse street networks, large blocks, and limited route options. These areas are commonly associated with rural landscapes, low-density suburban development, industrial districts, airports, or large parks where street connectivity is intentionally limited.
• Low Intersection Density: Neighborhoods with relatively few intersections and longer travel distances between destinations. While local circulation is generally adequate, walking and bicycling are often less convenient because the street network provides fewer direct routes.
• Average Intersection Density: Neighborhoods that provide a balanced level of street connectivity through a combination of connected streets and moderate block sizes. These areas generally support both walking and driving but may not offer the route flexibility found in traditional urban street grids.
• High Intersection Density: Well-connected neighborhoods characterized by frequent intersections, shorter blocks, and multiple travel routes. These street networks improve pedestrian accessibility by reducing travel distances and increasing route choice.
• Very High Intersection Density: Highly connected urban neighborhoods with dense street grids and numerous intersections that maximize accessibility for pedestrians, cyclists, transit users, and motorists. These neighborhoods are commonly found in historic downtowns, traditional mixed-use districts, and older urban neighborhoods.

Planning Implications

Intersection density is one of the most important measures of neighborhood connectivity because it directly influences how efficiently people can move through the built environment. Well-connected street networks provide shorter travel distances, greater route flexibility, and improved access to employment, schools, parks, transit, and commercial destinations. As a result, intersection density has become a widely used planning indicator for evaluating neighborhood accessibility, transportation efficiency, and walkability.

Research consistently demonstrates that neighborhoods with highly connected street networks encourage more walking and less automobile dependence. Cervero and Kockelman (1997) identified street design as one of the “3Ds” (Density, Diversity, and Design) that significantly influence travel behavior, while Frank et al. (2005) found that highly connected neighborhoods are associated with greater levels of walking and physical activity. Similarly, Ewing and Cervero (2010) concluded through a meta-analysis that street connectivity is one of the strongest built environment variables affecting travel patterns.

Neighborhoods with High and Very High Intersection Density generally require planning strategies that preserve existing connectivity while improving pedestrian safety through traffic calming, crosswalk enhancements, bicycle infrastructure, and complete street investments. Conversely, neighborhoods with Very Low or Low Intersection Density may benefit from long-term strategies that improve connectivity through new street connections, pedestrian pathways, trail systems, and redevelopment projects that reduce superblocks or isolated street patterns.

However, planners should recognize that not every low-density street network represents a planning deficiency. Airports, industrial facilities, reservoirs, military installations, and large parks often exhibit low intersection density because their land uses require limited public street access. Consequently, intersection density should always be interpreted within the context of surrounding land uses and local planning objectives.

Understanding Neighborhood Walkability

Street connectivity forms the physical framework that supports neighborhood walkability. At the neighborhood scale, intersection density measures how easily residents can move from one location to another using the local street network. Unlike municipal averages, neighborhood-level analysis reveals substantial differences in connectivity that often exist within the same city.

Neighborhoods with higher intersection density typically provide:

• More direct walking routes.
• Greater route choice for pedestrians and cyclists.
• Shorter block lengths.
• Improved access to destinations and transit.
• Better overall transportation network resilience.

These characteristics reduce travel distances while improving accessibility for multiple transportation modes. Traditional grid street networks often outperform suburban street systems because they provide numerous interconnected routes rather than relying on collector roads and cul-de-sacs.

Although intersection density is an essential component of walkability, it should not be interpreted in isolation. A neighborhood with a highly connected street network may still have poor pedestrian conditions if sidewalks are incomplete, traffic volumes are excessive, or destinations are lacking. Likewise, neighborhoods with lower intersection density may still provide pleasant walking environments when supported by trails, parks, or other pedestrian facilities. Therefore, intersection density should be evaluated alongside land-use diversity, transit accessibility, sidewalk infrastructure, pedestrian safety, and destination availability to develop a comprehensive understanding of neighborhood walkability.

Geographic Patterns in Neighborhood Walkability

Neighborhood-level intersection density exhibits clear geographic patterns throughout the United States. The highest concentrations of intersections are typically found within historic downtowns, traditional urban neighborhoods, university districts, and mixed-use commercial corridors that developed prior to widespread automobile-oriented planning. These areas generally feature compact blocks, interconnected street grids, and multiple route options that support efficient pedestrian movement.

Conversely, lower intersection densities are commonly observed in suburban subdivisions, industrial districts, airport complexes, large institutional campuses, parks, reservoirs, and environmentally constrained landscapes where development patterns naturally limit street connectivity. Many post-World War II suburban neighborhoods were intentionally designed around curvilinear streets and cul-de-sacs to reduce through traffic, resulting in fewer intersections and greater automobile dependence.

The dataset also demonstrates substantial variation within individual municipalities. Cities frequently contain neighborhoods spanning nearly the entire range of intersection density classifications—from highly connected downtown street grids to disconnected suburban developments located only a few miles away. These findings reinforce the importance of neighborhood-level analysis for identifying localized opportunities to improve connectivity rather than relying solely on municipal averages.

Overall, the observed geographic patterns closely mirror decades of planning research showing that historic urban development patterns generally produce higher street connectivity than more recent suburban development.

Overall Pattern

The neighborhood-level intersection density data demonstrate that street connectivity exists along a broad continuum rather than a simple distinction between connected and disconnected neighborhoods. Most neighborhoods fall within the middle categories, while the highest levels of connectivity are concentrated in compact urban districts developed using traditional street grid patterns.

Across the United States, neighborhoods with the greatest intersection density consistently occur in historic downtowns, mixed-use commercial centers, university districts, and older residential neighborhoods where compact block patterns maximize accessibility. Lower levels of connectivity are generally associated with suburban expansion, specialized land uses, and large undeveloped areas where street networks are intentionally less connected.

Perhaps the most important finding is that street connectivity is fundamentally a neighborhood characteristic. Significant differences frequently exist within the same municipality, demonstrating why neighborhood-scale analysis provides a much clearer understanding of walkability than citywide averages alone. When combined with the other components of the National Walkability Index—including transit accessibility, employment mix, and the balance between jobs and housing—intersection density provides planners with a valuable tool for identifying opportunities to improve accessibility, support active transportation, and create more connected communities.