@disabledsuicidegirl I think the reason more people go for the arm arteries (brachial, radial, or ulnar) is because with a tourniquet, you can get them to kind of pop out, meaning you can see them, and have easier access to sever. As you can see, in the leg, these arteries are covered by more muscle tissue, and it's hard to judge where they actually are. The veins you can see if you have light skin won't lose enough blood to completely bleed out, if you sever one of those.
View attachment 62073
Edit: Sorry, I didn't answer the question. I can't think of any reliable way of cutting a leg artery. The easiest one to get to would be the popliteal, behind the knee. But you still would have no way of actually seeing it to know where to cut.