In urban planning, walkability is the accessibility of amenities by foot. It is based on the idea that urban spaces should be more than just transport corridors designed for maximum vehicle throughput. Instead, it should be relatively complete livable spaces that serve a variety of uses, users, and transportation modes and reduce the need for cars for travel.
The term "walkability" was primarily invented in the 1960s due to Jane Jacobs' revolution in urban studies. In recent years, walkability has become popular because of its health, economic, and environmental benefits. It is an essential concept of sustainable urban design. Factors influencing walkability include the presence or absence and quality of footpaths, sidewalks or other pedestrian rights-of-way, traffic and road conditions, land use patterns, building accessibility, and safety, among others.
One proposed definition for walkability is: "The extent to which the built environment is friendly to the presence of people living, shopping, visiting, enjoying or spending time in an area". Walkability relies on the interdependencies between density, mix, and access in synergy. The urban DMA (Density, Mix, Access) is a set of synergies between the ways cities concentrate people and buildings, how they mix different people and activities, and the access networks used to navigate through them.
These factors cannot be taken singularly. Rather than an ideal functional mix, there is a mix of mixes and interdependencies between formal, social, and functional mixes. Likewise, walk-able access cannot be reduced to any singular measure of connectivity, permeability, or catchment but is dependent on destinations and geared to metropolitan access through public transit nodes. While DMA is based on walkability measures, popular "walk score" or "rate my street" websites offer more metrics to connect urban morphology with better environmental and health outcomes.
Density is an interrelated assemblage of buildings, populations, and street life.