Since Monday, US schools have been participating in the annual Walk to School Week, which encourages children and their parents to walk or bike to school. Supported by the U.S. Department of Transportation and the federal Centers for Disease Control and Prevention, the initiative seeks to engage children in simple physical activities that can help reduce obesity and stave off obesity-related illnesses. According to the National Center for Safe Routes to Schools Web site, more than 2,756 schools across all 50 states participated in Walk to School Day in 2007.