Modeled vs. perceived accessibility: Insights for urban planning

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Accessibility is an important factor for people’s activity participation, transport-related decisions and quality of life in general. For this reason, urban planners and researchers have been modeling and assessing accessibility using various mathematical models. However, when people go about their daily lives, they make decisions based on the way they perceive accessibility. Therefore, a lack of association between the two would be problematic for the use of modeled accessibility in planning.

“The findings suggest that on the one hand, the use of modeled accessibility for planning is relevant. On the other, they advocate for a more holistic approach, that integrates both modeled and perceived accessibility, to improve quality of life and transport-related decisions”, says Evangelos Vafeiadis, Doctor in Human Geography, who has investigated the relation between how accessibility to everyday activities is calculated using mathematical models and how it is perceived by individuals.

However, there is a surprising contrast for car users. Unlike other transport modes, decreased modeled accessibility for cars correlates with increased perceived accessibility. Evangelos emphasizes that this finding has significant implications for urban planners and policy makers and has to be interpreted with caution.

“It suggests that people in areas with lower modeled accessibility (which are typically more rural areas) may perceive higher accessibility using the car compared to people who live in areas with higher modeled car accessibility (closer to urban centers). This is because in less dense areas, the difference in modeled accessibility between the car and the other modes is far bigger than it is for urban areas. Therefore, people in rural areas may have no real alternatives; they are captive drivers. Improving modeled accessibility in these areas should not be seen as an attempt to decrease perceived car accessibility, but rather an attempt to increase perceived accessibility by other modes.”, says Evangelos Vafeiadis.

The study

The study, conducted in the Gothenburg region, explores the relation between modeled and perceived accessibility across four transport modes (bicycle, car, public transport and walking) and five everyday activities (commuting, grocery shopping, going for lunch, going for dinner and meeting a friend in the city center). Perceived accessibility was captured through a web-survey and modeled accessibility was calculated using three different accessibility models, each one emphasizing on a different aspect of accessibility such as shortest travel time, number of available alternatives within a specific time threshold and the decreasing effects of alternatives as travel time increases.