F-Shape barrier
The F-shape barrier is a concrete crash barrier, originally designed to divide lanes of traffic on a highway. It is a modification of the widely used Jersey barrier 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.