The present invention relates to a modular crash barrier system for impact absorption. The system comprises at least one post having a longitudinal direction, said at least one post being elastically deformable, said at least one post comprising at least one attachment groove defined by an inner wall and a first and a second side wall, said at least one attachment groove extending in said longitudinal direction. The system further comprises a protrusion arranged in said at least one attachment groove and connected to said inner wall, said protrusion having an extension along said longitudinal direction, at least one transverse barrier element comprising at least one attachment element slideably arrangeable within said at least one attachment groove for engagement with the protrusion, and wherein said inner wall, in an assembled state of the modular crash barrier system, is more prone to deformation than said first and second side wall in response to a force applied to said at least one post and caused by an impact to the transverse barrier element.