Abstract
<jats:p>This entry sheds light on two interconnected concepts in transportation and environmental studies, namely accessibility and exposure. Accessibility is referred to as the ease of reaching destinations. There are several ways of measuring accessibility, ranging from simple to complex, infrastructure‐centric to people‐centric, and place‐based to person‐based. Although accessibility measures have practical implications in transportation planning projects, there are substantial differences in the rigor of measures developed by researchers and those applied by practitioners. While participating in accessible activities, people are exposed to many environmental agents. The level of exposure depends on the places people travel to and the duration, time, and mode of travel. The integration of accessibility and exposure can be mutually beneficial. Rigorous accessibility measures can calculate scenario‐based potential exposure—which is crucial for evaluating the sustainability of projects or policies. Alternatively, accessibility measures can incorporate environmental costs, for example, cumulative heat exposure for grocery trips. This integration is also useful for evaluating social injustice by identifying undesirable areas marked by low access and high exposure. Besides methodological innovation, producing knowledge about built environment factors, access measure variations, and social inequality could be a future research frontier.</jats:p>