Reference · road & bridge standards

Bridge parapet containment height

Why a vehicle parapet's height is measured from the road surface, and the modern standard.

A vehicle parapet's job is to contain a vehicle on the structure. Its effective containment height is measured from the surface a vehicle travels on — not from the base of the wall. Raising the carriageway without raising the parapet reduces the effective height. Modern containment parapets are typically around 1.25m; below that, a wall can be mounted rather than stopping a vehicle.

Source: Design standards for bridge vehicle parapets (DN-GEO-0303 and related). General standard, stated for reference only.

A reference page explaining a published road or bridge standard. It states the standard only; it makes no claim about any particular location.

Last updated 2026-08-05. This is a living record — findings are added as dated entries and prior versions remain visible.