A collision detection system for a vehicle includes a bumper reinforcement fixed to a side member of the vehicle, a pressure sensor placed in front of the bumper reinforcement and having at least one pressure-sensitive member, and a load plate placed in front of the pressure sensor. The load plate has a base member and at least one leg member extending from the base member toward the bumper reinforcement. The base member has a first portion facing the pressure sensitive member of the pressure sensor and a second portion fixed to the leg member. The pressure sensor can have a small pressure-sensitive range, because the leg member reduces pressure applied through the load plate to the pressure sensor.