Commuting and the Spatial Mismatch: A Foregone Accessibility Approach

The influence of urban structure on commuting efficiency has long been a central topic in urban and transportation research. Most traditional measures of commuting efficiency, such as excess commuting, rely primarily on distance and, occasionally, travel time. While useful, these proximity-based metrics fail to capture the spatial distribution of jobs and workers. Accessibility, defined as the ease of reaching destinations, offers a more comprehensive framework for addressing this limitation, as it considers the distribution of activities across space. We adopt the cumulative opportunities measure, which counts destinations reachable within a given time or distance threshold, replacing that threshold with the observed commuting distance. We call this “foregone accessibility,” defined as the share of citywide jobs located within a worker’s observed commuting distance that they do not take up or interact with. We compare observed commuting distance and foregone accessibility across different employment sectors for both workers and jobs in Greater Montreal, based on their levels of concentration and dispersion. Our findings reveal that foregone accessibility and observed commuting distance are not always positively correlated; in some cases, the relationship is negative. High commuting distances tend to be associated with low foregone accessibility, suggesting that some areas lack employment opportunities nearby, compelling residents to travel long distances. This highlights the limitations of relying solely on distance-based measures and underscores the need to adopt accessibility-based metrics. Such an approach is particularly relevant for urban planning, as it captures not only proximity but also the spatial distribution of employment opportunities across a city.