Turn Your Bike Into A Paintbrush.

Contrail by Ulicu LLC from Teresa Herrmann on Vimeo.

When the Brooklyn-based designers Pepin Gelardi and Teresa Herrmann entered a competition to design a bike accessory that would draw new cyclists, they began by examining the reasons people avoided riding. “The number one barrier to entry was that people felt unsafe and outnumbered by cars,” Gelardi says. “We wanted to create a device that proved to potential cyclists that a community exists.”

Figuring that a simple way to extol that community was to literally chart its crisscrossing paths, the pair came up with Contrail, a receptacle filled with colorful chalking fluid that attaches to a bicycle’s frame and leaves a bright line in the rider’s wake.