Whether mode choice yields expected impacts on daily activity level remains an open question. Available research confirms declining activity levels for children (Dietz and Gortmaker, 2001; Trost et al, 2002) and adolescents (Sallis, et al, 2000). However, studies evaluating the role of walking to school have been mixed in finding statistically significant increases in children's daily activity level (Krizek et al, 2004). For example, one study found no effect on total activity for five-year-olds driven to school (Metcalf et al, 2004); another found increased total activity correlated with walking to school, yet with statistical significance only in boys (Cooper et al, 2003). .
