It is increasingly important for transit decision makers to ensure that service is provided to those with mobility disadvantages. This is a large group spanning those without cars (not by choice) to persons with disabilities and the elderly who are no longer able to operate personal vehicles. Resources that help planners identify areas of need can increasingly be created with the widespread availability of digital tools and open data that allow the measurement of transit performance. One approach is to map accessibility to different types of destinations for metropolitan areas and to evaluate if areas of need, based on resident profiles, are receiving adequate level of service. Earlier this year, a research team from the University of Illinois at Chicago debuted the Metropolitan Chicago Accessibility Explorer, an interactive digital resource to measure access to destinations in metropolitan Chicago by public transit as well as other modes. Using the Explorer, planners and those who can shape policy now have a new tool to use when planning future transportation expansion or improvement projects. Resources like the Explorer can be of use in just about every market in the nation.