As cities vie to attract talented college graduates and sustain population growth, they are focusing attention on parks to increase livability and support a strong economy. Since parks must be convenient if they are to provide their benefits, many places have set goals for the maximum distance any resident should be from the nearest park. But the goals vary widely, from an eighth of a mile in Chicago to two miles in Atlanta. Many people wonder if it is even possible to establish a universal standard.

This is a complex question. An individual's willingness to walk varies greatly depending on age, health, time availability, quality of surroundings, safety, climate, and many other factors. On top of the variability in walking patterns, a city's density has a bearing on what is considered a reasonable distance and where it is cost effective to add new parks.

The majority of walking studies are for and about commuters. Broadly speaking, they indicate that most people are only willing to walk a quarter-mile as part of a commute. A New York Regional Plan Association study, for example, found that residents within a quarter-mile of a transit facility are 5 to 7 times more likely to walk to the station than other passengers.[1]

The quarter-mile standard is also supported by park equity research. Jennifer Wolch, now at the University of California at Berkeley, wrote in 2002 that a quarter-mile is reasonable "for parents taking toddlers and small children to a park for everyday outings and playground opportunities."  In the context of Los Angeles, she noted, "trips of more than a quarter mile (especially in high-traffic areas or neighborhoods where parents have safety concerns) are unlikely to be acceptable to parents."[2] 

Conversely, several studies show that a half-mile walk is well within a reasonable distance for most people. The 2002 National Survey of Bicyclist and Pedestrian Attitudes and Behavior, by the National Highway Traffic and Safety Administration and the Bureau of Transportation Statistics, surveyed almost 10,000 people over the age of 16 and found that only 5 percent of walking trips were for getting to work. [3] (This suggests that transit studies should not be too heavily relied upon to determine a reasonable distance to a park.) Of the other trips, 38 percent were for personal errands, 28 percent were for exercise, and 21 percent were for recreation or leisure. The average trip length was 1.3 miles.

A 1976 study of the Bay Area transit system found that only 50 percent of riders who walked to the facility came from within a six-minute walk, but 80 percent came from within ten minutes, or approximately a half-mile.[4] This data supports cities that set a standard of a half-mile (and in some cases, more) as a reasonable distance to walk to a park. Perhaps the crux of the issue is: do people consider walking to the park a chore, or is the walk part of the recreational experience itself?

This isn't as funny as it sounds. A 1997 study from Austin, Texas stated that "utilitarian and recreational walk activities have been found to have distinct structural characteristics.…Walk distance and duration for commuting, shopping, and reaching transportation are shorter, and recreational walks for exercise, walking the dog, and socializing are longer."[5] 

Transit-based studies also underscore people's variability: most won't walk much more than a quarter-mile to a bus stop, but most will walk up to a half-mile to a commuter rail station. Parks, too, draw pedestrians from "catchment areas" of various sizes, depending on their quality and amenities offered. In a 2002 article, Van Herzele and Weidemann note that "the maximum walking distance may differ according to the function a green space fulfils."[6]

In summary, research supports the validity of both quarter-mile and half-mile distance goals, depending on perceptions of the built environment, safety, and time constraints. Of course, people's preferences and habits are only part of the equation for planners, who must also take into account the cost effectiveness of expanding the park system versus improving current parks or focusing on connectivity.

Density is a major factor. Building a new park in a low-density area (5 units per acre) provides access to only about 1,500 people within a quarter-mile range.  In a very dense area (90 units per acre) it serves close to 30,000. So even if planners in, say, Charlotte found a reluctance to walk more than a quarter-mile to a park, the city still probably could not afford to build a park for every 1,500 residents.

The following table illustrates the total population within quarter-mile and half-mile buffers in areas of varying density: