Specialized bumpers, known as "bull bars" or "roo bars", protect vehicles in rural environments from collisions with large animals. However, studies have shown that such bars increase the threat of death and serious injury to pedestrians in urban environments, because the bull bar is rigid and transmits all force of a collision to the pedestrian, unlike a bumper, which absorbs some force and crumples. In the European Union, the sale of rigid metal bull bars that do not comply with the relevant pedestrian-protection safety standards has been banned.