Data from 1,947 pedestrian crossing events measured at 11 intersections in Madison and Milwaukee, Wisconsin, were analyzed to determine the effect of subject age and disability, intersection traffic control condition, group size, and sex on walking speed. A multifactor analysis of variance indicated that pedestrian walking speed depended on age and disability, traffic control condition, and group size. Pedestrians older than 65 (n = 326) were the slowest of all age groups, with mean and 15th percentile walking speeds of 3.81 and 3.02 ft/s, respectively, and typically would not be accommodated by pedestrian clearance intervals based on the commonly used 4.0-ft/s walking speed. Adult-assisted children and physically disabled persons had crossing speeds similar to those of persons older than 65. Groups of pedestrians crossed 0.4 to 0.6 ft/s slower than individuals. On the basis of data reported here, a 3.8-ft/s walking speed is recommended for timing pedestrian clearance intervals (flashing don't walk indication) at locations with normal pedestrian demographics (downtown areas, shopping areas, most neighborhoods, school areas) and locations where the age or physical disability status of the pedestrian population is unknown. When the proportion of pedestrians over the age of 65 is equal to or exceeds 20%, 30%, 40%, 50%, and 100% of the total pedestrians at a location, walking speeds of 3.6, 3.5, 3.4, 3.3, and 2.9 ft/s, respectively, are recommended for pedestrian clearance timings. Walking speeds of 4.0 ft/s are appropriate only for locations with very few older pedestrians, assisted children, and disabled persons, such as college campuses.