A vehicle crash barrier (10) for decelerating a vehicle that has left a roadway includes an elongated frame having a number of sections (14, 16, 18) including a front section (14) and at least one additional section (16, 18) arranged end to end along an axial direction. The frame is configured to collapse when axially struck on the front section (14) by a vehicle. The front section is releasably secured to a ground anchor (80) by a directionally sensitive breakaway assembly (100). A wire cable (122) extends generally parallel to the frame and has a forward end portion anchored independently of the frame and a rearward end portion. Friction brakes (140) are mounted to the front section for engaging the wire cable (122) during collapse of the frame following impact of the vehicle against the front section (14). Each section includes a pair of side panels (42), and axially adjacent side panels are connected by a flexible tension strap (46) by fasteners (44). The tension strap (46) operates to peel the fasteners (44) out of the side panels (42) during axial collapse.