If you must stop on a one-way or divided highway, where should you place your three warning triangles?

49 CFR 392.22(b)(2)(v) (placement on a one-way or divided highway); AAMVA CDL Manual Section 2.5.2, p.2-12, Fig 2.8

On a one-way or divided highway, all three triangles have to warn traffic approaching from the single direction it can come from; placing them wrong, or too close together, cuts the warning distance a fast-moving vehicle needs to react safely. The 10/100/200-foot spacing is a specific, commonly tested numeric fact.