What is the term for the distance a barrier will displace upon impact?

The term "barrier deflection" refers specifically to the amount of movement or displacement a barrier experiences when it is struck by a vehicle. This is a critical factor in traffic safety as it affects the effectiveness of the barrier in absorbing the impact and protecting both the vehicle occupants and other road users. Understanding barrier deflection helps engineers design safer infrastructure by ensuring that barriers can withstand impacts without allowing vehicles to penetrate protected areas.

Other terms like barrier setback and impact distance might relate to the positioning of barriers or the distance required to stop a vehicle, but they do not specifically describe the displacing motion of the barrier upon impact. A safety margin, while relevant in terms of ensuring adequate space for safety, does not specifically address the concept of deflection. Thus, barrier deflection is the correct and most precise term for the described phenomenon.