This paper presents an approach to the development of mixed-priority pedestrian delay models at single-lane roundabouts by using behavioral crossing data. “Mixed priority” refers to crosswalk operations in which drivers at times yield to create crossing opportunities but pedestrians may need to rely on their judgment of gaps in traffic to cross the street. The models use probabilistic behavioral parameters measured in controlled pedestrian crossings by blind pedestrians as part of NCHRP Project 3-78a. Although blind pedestrians clearly represent a special population of pedestrians, the developed delay model is structured to apply to any pedestrian population. Delay is predicted as (a) a function of the probability of encountering a crossing opportunity in the form of a yield or crossable gap and (b) the probability of taking that opportunity, and these factors are combined to produce an overall probability of crossing. The paper presents the theoretical approach to estimating the probability parameters and uses a multilinear, log-transformed regression approach to predict the average pedestrian delay. The final delay model explains 64% of the variability in the observed data and therefore represents a reasonable model for predicting pedestrian delay at single-lane roundabouts. The paper concludes with a discussion of how agencies can estimate the underlying probability parameters for existing or proposed roundabouts by using empirical and theoretical approaches and how pedestrian crossing treatments can be used in the context of the model to reduce average pedestrian delay. The research is important in light of the ongoing debate on the accessibility of modern roundabouts to blind pedestrians.