Walking and bicycling are two of the easiest ways to be active. One of the main goals of most Safe Routes to School (SRTS) programs -- along with increasing safety -- is to increase the numbers of children who walk and bicycle to school. Some local SRTS programs are expanding that goal to include encouraging healthy, active lifestyles from an early age. However, little is known as to whether walking or bicycling to school leads to an overall increase in physical activity. The question explored in this research-based report is: does walking and bicycling to school actually increase physical activity? And, if so, how can local SRTS programs measure this increase?