Older pedestrians are over-involved in serious injury and fatal crashes compared to younger adults. This may be due, in part, to diminished perceptual, cognitive and motor skills which act to reduce the older person’s ability to sense danger and take measures to avoid hazards. Two experiments are described in this paper which examine age differences in gap selection decisions in a simulated road crossing environment. The results demonstrated age differences in the decision-making process, particularly a difficulty in estimating appropriate time-of-arrival of oncoming traffic along with an inability to allow for slower decision times and walking speeds. A two-phase model of road crossing decisions is discussed within a limited information processing approach and it is suggested that older adults experience problems in quickly and instantaneously calculating distance and velocity information in order to select safe margins in which to cross the road.