A vehicle crash barrier constructed primarily of structural tube members having an energy-absorbing connection between horizontal rail members and vertical post members. Horizontal rail members are provided with one or more deformable flanges adjacent to each end to be connected to a vertical post member. Vertical post members include a channel adjacent a top end for receiving the rail end and flange. The rails are connected to the vertical members by downwardly sliding the flanged end into the vertical channel until the rail rests upon a bottom stop. A reinforcing cap is positioned on the top end of the vertical member to prevent upward movement of the rail and to strengthen the vertical post structure. Shims may be installed between the flange and the channel walls to limit horizontal rail movement.