A highway guardrail terminal having horizontally extending guardrail elements mounted on a plurality of vertical posts. An anchor cable release mechanism having a cable release bracket attached to a W-beam rail element by cable release bolts has an arrangement of tapered slots and elongated openings to quickly release the cable release bracket from the W-beam rail element upon end-on vehicular impact to the terminal. The tapered slots have a geometry which lifts the bracket away from and out of a parallel alignment with the W-beam rail element.