The F-shape barrier is a

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...

crash barrier Traffic barriers (sometimes called Armco barriers,AK Steel (formerly Armco) genericized trademark also known in North America as guardrails or guard rails and in Britain as crash barriers) keep vehicles within their roadway and prevent them fro ...

, originally designed to divide lanes of traffic on a

highway A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to controlled-access ...

. It is a modification of the widely used

Jersey barrier A Jersey barrier, Jersey wall, or Jersey bump is a modular concrete or plastic barrier employed to separate lanes of traffic. It is designed to minimize vehicle damage in cases of incidental contact while still preventing vehicle crossovers resu ...

design, and is generally considered safer. A parametric study, one that systematically varies the parameters, was done through computer simulations of barrier profiles labeled A through F. The result showed that the one labeled F performed better than even the shape of the Jersey barrier. A series of full-scale crash tests later confirmed these computer-based results. What is known today as the F-shape barrier takes its name from these tests and not from any part of the shape of the barrier, unlike, for example, T-walls. In spite of these tests, the F-shape barrier has not supplanted the Jersey-shape. The Jersey-shape barrier was already in wide use, and it also met the crash-test criteria. The states' contractors already had a significant investment in the Jersey-shape casting forms and it would cost them money to change the profiles of the forms. The F-shape and the Jersey-shape have the same slopes, but the distance from the ground to the slope break point of the F-shape is , which is lower than the Jersey-shape. This lower slope break point reduces vehicle lift, improving the barrier's performance. Because the Jersey-shape design requires very little modification to become an F-shape design, asphalt resurfacing can convert the Jersey-shape barrier into a more F-shape-like barrier that is safer for lighter cars. However, these increased layers of asphalt also reduce the working height of the barrier which reduces its effectiveness for heavier vehicles. The UK equivalent is the

concrete step barrier A concrete step barrier is a safety barrier used on the central reservation of motorways and dual carriageways as an alternative to the standard steel crash barrier. United Kingdom With effect from January 2005 and based primarily on safety ...

References

Protective barriers Road safety {{Road-stub

See also

References