Bolt comprising a three-dimensional body substantially extended along a first direction defined on a first axis (X), having at least one side wall (401), a tip portion (405) adapted in use to first contact the ground or road surface and a head portion (402), axially opposite to said tip portion, wherein in correspondence of said side wall (401), in an intermediate position between said head portion (402) and said tip portion (405), there is a retention flap for extraction (406), said retention flap for extraction (406) extending outside the profile of said at least one side wall (401) and being inclined with respect to the latter with an obtuse angle with respect to said first direction; said retention flap for extraction (406) exerting a counter-action on the ground if said bolt (400) is subjected to an extraction force from said ground or road surface.