Thousands of students will hit the sidewalk instead of the school bus Wednesday on International Walk to School Day.

The event, sponsored by the Partnership for a Walkable America, started in Chicago in 1997. What began as a one-time event to promote walkable communities became international in 2000, when the partnership in the U.S. teamed up with schools in Canada and the U.K.

Now in its 12th year, the event is expected to draw celebrations at 3,626 schools across the country Oct. 3; even more are expected in 40 other countries worldwide. The goal: raising awareness about safer routes for walking and bicycling to school, traffic congestion, pedestrian safety and increased activity for kids, the organization says.

Last year was the first year Fairfax County Public Schools formally endorsed the event; this year, about 35 schools within Fairfax County Public Schools are participating, said Wolftrap Elementary's Safe Routes to School coordinator Jeff Anderson.

Hunters Woods Elementary is the only Reston school with a formal event Wednesday, but with 55 miles of bike paths in Reston, many Restonians walk to their neighborhood school regularly.

Kiss and Ride crowding has been a growing problem across the county, and advocates say using International Walk to School Day as a springboard for more regular walking or biking programs could offer a permanent solution.

FCPS School Board Chair Ilryong Moon and Fairfax County Board of Supervisors Chair Sharon Bulova issued a joint statement last week encouraging parents and their children to lace up their sneakers for the event.