In an embodiment, a road barrier energy absorption unit can comprise: a vehicle crush section configured to absorb impact energy when impacted with greater than or equal to 5 kN force; a post channel configured to receive a road barrier post; and a guardrail attachment. The energy absorption unit can be disposed over the post and a guardrail can attach to the energy absorption unit. In an embodiment, a road barrier energy absorber system comprises: posts; road barrier energy absorption unit; and a guardrail extending between the energy absorber units. Each post is disposed in one of the energy absorber units. The energy absorber units comprise a vehicle crush section configured to absorb impact energy when impacted with greater than or equal to 5 kN force. In an embodiment, a guardrail can comprise: an outer wall and stiffening elements, wherein the guardrail comprises a plastic.