Many cities lack the infrastructure needed to really keep cyclists safe on urban roads, but in Wichita, Kansas, some cyclists are striking back against cars creeping into their dedicated lanes. With toilet plungers.

According to CityLab and KSN, a mystery bicycling activist recently set up toilet plungers with reflective tape along the edge of a bike lane in downtown Wichita in a moment of DIY urban design. The plungers act like the bollards that some cities use to create a physical barrier between bikes and vehicle traffic, giving drivers a visual reminder that they’re not legally allowed to cross over into the bike lane. From a legal standpoint, plunging the roads is technically littering, but it was for a good cause.

Bike lanes can have a major impact on traffic safety in a city. Riders tend to be safest when riding in protected lanes, meaning lanes that have a physical barrier between the bike lane and other traffic. When New York City installed the first protected bike lane in the U.S. in 2009, the city saw a 58 percent decrease in injuries—among pedestrians, cyclists, and drivers—on those streets [PDF]. Intersections tend to be particularly dangerous, because drivers don’t always see cyclists while turning: in 2014, about a third of the bicycle fatalities in the U.S. occurred at an intersection.

While Wichita has been taking some steps to create new bike lanes and make cycling safer for its residents, an anonymous bike lover is just prodding drivers to stay in their lane. This kind of guerrilla bike infrastructure isn’t unheard of; cycling and pedestrian safety activists have previously set up cones, traffic delineators, flower pots, and more to stake their territory on traffic-clogged streets. Occasionally, these makeshifts even become permanent. Wichita's plungers were only a temporary installation—though there were still some left up a week after the intervention—but perhaps the city will notice that cyclists enjoy the extra protection.

[h/t CityLab]