Abstract: Guardrail assembly is performed by a vehicle carrying an inventory of guardrail sections and guardrail support blocks. The vehicle moves along a series of prepositioned guardrail posts and includes a side-mounted support frame allowing joining of guardrail sections and deployment rearward of a continuous ribbon of joined guardrail sections. As the continuous ribbon of joined guardrail sections is deployed, it is urged laterally outward and against attachment sites of the series of prepositioned guardrail posts. The continuous ribbon is then attached to the guardrail post, including mounting of an intermediate support block. The assembly and mounting under the disclosed method and apparatus is approximately half that of conventional guardrail assembly and mounting.