Table 2 Definition of categories used in the synthesis of results

Availability and accessibility of destinations

Presence of or ease of access to places offering some type of service or goods where people go with a purpose, such as shops, churches, schools, workplaces, etc. Destinations within walking or cycling distance are expected to increase active travel and thus PA [14].

Availability and accessibility of places for exercise or recreation

Presence of or ease of access to indoor and outdoor spaces and facilities designed for exercise or leisure activities, including parks, swimming pools, walking trails, fitness centers, etc.; these places provide opportunities for leisure-time PA and are therefore expected to be positively associated with PA [34].

Availability and accessibility of public transport

Distance to or density of public transport stops (e.g., railway station or bus stop); a shorter distance to as well as a higher number or density of public transport stops is expected to increase walking and thus PA [35, 36]

Overall accessibility

Presence of or ease of access to places or public transport; better accessibility means shorter distances and shorter distances are expected to increase active travel and thus PA [14, 36].

Density

Population or dwelling units per unit area [35]; high residential or population density is expected to be positively associated with walking and PA, as it reduces distance and time of travel between residences and destinations [36].

Land use

Type of use of physical space within a given area (e.g., residential, commercial, industrial, agricultural); mixed land use providing nonresidential destinations is expected to be associated with more walking and PA [36, 37].

Connectivity

Characteristics of the street design that facilitate direct travel between two points, such as a high intersection density, alternative routes, and more street integration; higher connectivity is expected to increase walking and cycling by providing more potential routes and shorter distances to destinations [36, 37].

Pedestrian infrastructure

The presence and quality of sidewalks (including maintenance, width, absence of obstructions) are expected to be positively correlated with walking [36].

Cycling infrastructure

The presence and quality of bicycle lanes/paths (including maintenance, width, absence of obstructions) or bicycle-friendly streets are expected to be positively correlated with cycling [38].

Safety and security

Safety refers to pedestrians and cyclists being protected from motorized traffic by low traffic volumes or safety and traffic calming infrastructure (e.g., buffers, crosswalks); security refers to pedestrians being protected from crime and incivilities, mostly by street lighting; higher safety and security are expected to be associated with higher walking, cycling, and PA [36, 39].

Aesthetics

Presence of interesting sights, maintenance, cleanliness, and absence of physical disorder; aesthetics is expected to be positively associated with leisure-time PA and walking [36].

Greenness/ natural environment

Elements of nature, such as trees, grass, plants or water, or the greenness of an environment are expected to be positively associated with outdoor leisure-time PA and walking [12].

Hilliness

Hilliness/an increased slope makes walking and cycling more difficult and is therefore expected to be negatively associated with transport-related PA [20].

Overall environment

An overall rating of how the physical environment enables or hinders PA; often multidimensional and combines the dimensions described above into an index or overall score [39].