Insidiatio viarum is a Latin term which means lying in wait for one on the highway. It is a species of felony that includes the crime of waylaying someone along the roadway. In insidiatio viarum the benefit of clergy was denied even by the common law.
In Anderson v. Hartford Acci. & Indem. Co., 77 Cal. App. 641, 647 (Cal. Ct. App. 1926), the court observed that "Highway robbery insidiatio viarum was excluded from clergy at common law previously to Statute 25, Edw. III, Pro clero; 4 Bl., 373; 1 Chit. Cr. Law 675; 2 Hale, 333. The Statute Pro clero gave clergy for any treasons or felonies not touching the King himself or his royal majesty. Yet a construction prevailed after this that insidiatores viarum might be denied it. Hale & Haw, ubi supra. The reason [***10] assigned being that it was a sort of hostile act and bordered upon treason. 4 Bl. 373; 1 Ch. Cr. L., 675. Upon complaint of this to Parliament, the Stat. 4, H. IV, chap. 2, granted it [*647] to them. The reason above grew out of the fact that the King had a right of passage for himself and for all of his subjects. Comyn, Chemin (A, 2), page 27. Where highways are unsafe, the whole country is in peril. The policy of this security applies only to places where every citizen has a right to pass and repass at pleasure; particularly to such upon which every man is sometimes compelled to be; and to transport articles of value; and expose such at lonely places; at the same time that the robber himself cannot be excluded from being thereupon, having the right to pass and repass as well as others, and being under the protection of the sovereign in the enjoyment of his right."