Support structure adapted to form a collision object for use when testing a subject vehicle to simulate a real traffic environment, the support structure comprising a plurality of panels having a bending stiffness according to ISO 5628:2012 of 20 Nm to 60 Nm, such as 30 Nm to 50 Nm, such as 35 Nm to 45 Nm. A support structure adapted to form a collision object for use when testing a subject vehicle to simulate a real traffic environment, the support structure comprising a plurality of panels made from cardboard, is also provided. A collision object for use when testing a subject vehicle to simulate a real traffic environment is also provided.