Devices and methods for supporting guardrail terminal installations that incorporate safety end treatments such as the GET and the SRT. Preferred embodiments are described wherein guardrail terminal installations are primarily anchored to the ground using weak support posts that are preferably made of metal. The ends of the guardrail installation are secured to the ground using breakaway posts. In operation, the weak posts permit the central portion of the guardrail installation to contain and redirect the vehicle during a lateral collision to the rail member. The anchorage provided by the breakaway end posts helps prevent the guardrail from being excessively displaced, thus preventing the impacting vehicle from breaking through the guardra...