Objective: In many countries, pedestrian light crossings require a minimum walking speed of 1.2 m/s. This study examined the proportion of adults in a nationally representative sample whose usual and dual-task walking speeds are <1.2 m/s. Method: Community-dwelling adults aged ≥50 years in The Irish Longitudinal Study on Ageing (TILDA) completed walking speed tests on a GAITRite® walkway (N = 4,909). Results: One third of Irish adults aged 65 to 74 years and 61% of adults aged ≥75 years walked slower than 1.2 m/s. In dual-task walking, 54% of adults aged <65 years and 91% of adults aged ≥75 years walked slower than 1.2 m/s. Discussion: Based on these data, many older people would have insufficient time to cross the road at light-controlled pedestrian crossings. Increasing the time provided would be an advantage for many older pedestrians.