An energy-absorbing system includes a tube made of a continuous material, such as heat-treatable steel. The tube has first and second ring sections connected by an intermediate section. In one aspect,the intermediate section is flared and/or pinched to cause one tube section to predictably telescopingly roll upon impact. In another aspect, one section is annealed to optimize elongation and yieldproperties to facilitate rolling upon impact. By this arrangement, upon the bumper system receiving a longitudinal impact, the first and second ring sections telescopingly collapse with a predictableand consistent rolling collapse. Methods related to the above are also disclosed.