Front structure of a vehicle

A front structure of a vehicle, the front structure comprising:

• a bumper;
• first and second side members arranged in a longitudinal direction of the vehicle at a left-side portion and a right-side portion, respectively, of a front portion of the vehicle;
• first and second crash boxes located behind the bumper, the first crash box being arranged at a front end of the first side member, and the second crash box being arranged at a front end of the second side member, the crash boxes having a lower axial strength than the side members;
• and
• a body back-up structure located at a rear end of the front portion and connected to the side members;
• wherein the front structure is adapted to give an impact response curve with deceleration versus time, when subjected to a full frontal barrier impact at 35 mph, the impact response curve having in sequence
• a first phase during which deceleration increases,
• a second phase forming a first peak level of the deceleration,
• a third phase during which the deceleration is less than during the second phase, and
• a fourth phase forming a second peak level of the deceleration, during which fourth phase the deceleration is greater than during the third phase.