In its letter to Ames, which was shared with The New York Times, the highway administration said that crosswalk art “diminishes the contrast between the white lines and the pavement, potentially decreasing the effectiveness of the crosswalk markings and the safety of pedestrian traffic.”

“The purpose of aesthetic treatments and crosswalk art is to ‘draw the eye’ of pedestrians and drivers,” it continued, “in direct conflict with commanding the attention of drivers and motorists to minimize the risk of collision.”

But urban planning practitioners and advocates say the government’s claims that crosswalk art makes intersections less safe are not rooted in evidence…

“There are hundreds around the country, if not thousands around the world, and I don’t know of any study that has been able to show that they are actually causing any problems,” Mr. Lydon said.