Marathons wreak havoc on city traffic. But what about pedestrians who just want to cross the street? Marathon organizers have developeda multistep system that is a pretty damn creative way of moving pedestrians across the race course without disrupting the race.

Here’s the system in action:

At one end, volunteers use a string to funnel racers toward one side to allow groups of pedestrians to cross. A fancier solution? Temporary bridges, such as these used during the London Marathon.