Bumper reinforcement member

A bumper reinforcement member comprising:

• a front reinforcement member including a front intermediate face and a pair of front grooves, the front intermediate face being a portion of a bumper front face, and the pair of front grooves being arranged above and below the front intermediate face and being recessed from the bumper front face;
• and
• a back reinforcement member including a back intermediate face and a pair of back grooves deeper and wider than the pair of front grooves, the back intermediate face being positioned on the front side than bottom faces of the pair of front grooves, and the pair of back grooves being arranged above and below the back intermediate face and being recessed from the bumper front face;
• wherein
• the back reinforcement member is coupled to the front reinforcement member,
• the pair of back grooves contain therein the pair of the front grooves,
• the bottom faces of the pair of front grooves and the bottom faces of the pair of back grooves are not in contact with each other, and
• the front reinforcement member and the back reinforcement member satisfy both of following equations;
• B=( 1/10 to ½)L
• 0≦A< 1/10L
• wherein, B is a depth of the pair of front grooves from the bumper front face to the bottom faces of the pair of front grooves, L is a depth of the pair of back grooves from the bumper front face to the bottom faces of the pair of back grooves and A is a smallest distant from corners connecting upper lateral faces or lower lateral faces and the bottom faces of the pair of front grooves to an opposing upper lateral faces or an opposing lower lateral faces of the pair of back grooves.