IntroductionMeasuring the effect that transportation interventions have on accessibility can be broadened by incorporating potential opportunities for social exposure, particularly with diverse others. MethodsIn this paper, we employ a modified social interaction potential (SIP) approach to measure changes in exposure to diverse populations based on the addition of new bus services to the transit network. SIP is a metric employed in transportation geography research to measure opportunities for engagement by describing the theoretical potential for colocation. DataIndividual-level, origin-destination data from a survey of passengers on a newly added bus to the Southeastern Pennsylvania Transportation Authority’s (SEPTA; Philadelphia metropolitan area) network is analyzed. ResultsA SIP-based index of opportunities for exposure to sociodemographic diversity are demonstrated and changes to SIP around the addition of the new bus route are measured. The results of paired t-tests signal that the addition of this new route to the network is associated with a statistically significant increase in the opportunities for exposure to income and age diversity, as compared to index values measured using likely transit travel patterns utilized before the addition of the new route. ConclusionTransportation planning efforts meant to promote greater accessibility to material opportunities through new transit alignments may also expand accessibility to social opportunities. We advance a methodological approach that crafts a nuanced portrait of accessibility that can help to orient future transportation planning policy. Future analyses employing this approach will benefit from larger, administratively provided, individual-level datasets that describe greater segments of the population.