An apparatus for protecting an elongated structural support from impact, said apparatus comprising: a plurality of elongated impact protection components (14, 16) configured to fit together beside each other in installed positionss in which said components define transversely adjacent segments of an elongated impact protection body that surrounds the structual support (12); each of said components (14,16) having a peripheral side wall (52, 82) with a rear portion (82, 40) configured to mate with the structual support (12) upon movement of the component transversely into its installed position; each of said side walls (52, 82) surrounding a respective air chamber (56) and further having a front portion ( 52) configured to deflect inwardly toward said rear portion (82, 40) so as to reduce the volume of said respective air chamber (56) upon the impact of a vehicle or the like, and thereby to protect the structural support (12) from said impact.