Abstract
Since they were first used on motorways in the sixties; deformable steel barriers (guardrails) have become increasingly standarized. This process of standardization consists, among other things, of a coding system which includes all types of construction (flexible, rigid and semi-rigid). Positioning criteria are also available. The barriers as a whole must fulfil a number of functional requirements. In addition, there are separate functional and design requirements for the various parts. This document contains these requirements for deformable constructional changes. Entirely new concepts for deformable steel barriers are also possible.