A Student Pedal-Powered School Bus
They are not exactly walking, but the concept of working together to use their own energy to get themselves to school is a great idea! (Weather permitting of course). It helps with fitness levels in kids, since obesity is becoming a global phenomenon these days, better for the environment as opposed to fuel-powered vehicles etc.
The vehicle is made by De Cafe Racer in the Netherlands, but is unfortunately only available for a day hire at the moment, for fun, rather than for commuting purposes.
First image: http://www.thekindlife.com/post/pedal-power-back-to-school
Second image: http://www.wired.com/gadgetlab/2011/06/pedal-powered-school-bus-cuts-kids-calories/