When I was a kid, I walked to and from school twice every day: once at the beginning and end of the day and once for lunch. In fact, I'm one of the few people I know who never rode a school bus.
If more kids did this, we'd have healthier children, less congestion, and better air quality. That's what the Partnership for a Walkable America was thinking when it launched National Walk Our Children to School Day in 1997. (My school days were long gone by then, and it showed.)
In 2005, federal surface transportation legislation launched Safe Routes to School (SRTS) and gave state DOTs money to administer SRTS programs. The National Center for Safe Routes to School was established the next year to help local governments get their hands on that money (which became more difficult when NEW surface transportation legislation eliminated dedicated funding).
Anyway, the center's a great resource. Every year, it enlists elected officials, public agencies, parents, teachers, students, to raise awareness of walking's benefits by participating in a national day of recognition. You don't have to register to hold an event or plan a safety initiative, but you can use free materials (logos, booklets, annual reports, etc.) to design an activity that will get people's attention.
Now if you'll pardon me, I think I'll go take a walk.