ed_freire

To the uninitiated, the term, "transversal crown trenches," is ambiguous. A diagram is needed for clarification.

Nevertheless if these drains or trenches are built to prevent earth or rock slides, they most likely will be: "Drenes contrafuertes."

Now "drenes contrafuertes" are "transversal" to the centerline of the highway (not to the slope, as one might imagine). So check the context of your article and preferably inspect any diagram it might have to verify that the "transversal crown trenches" alluded to are in fact drains slung down from the top of the slope to the highway shoulder (to be expected logically).

If they are, translate them as "drenes contrafuertes" (singular: "dren contrafuerte").