  An induced matching in a graph $G$ is a matching such that its end vertices
also induce a matching. A $(1^{\ell}, 2^k)$-packing edge-coloring of a graph
$G$ is a partition of its edge set into disjoint unions of $\ell$ matchings and
$k$ induced matchings. Gastineau and Togni (2019), as well as Hocquard, Lajou,
and Lu\v{z}ar (2022), have conjectured that every subcubic graph is
$(1^2,2^4)$-packing edge-colorable. In this paper, we confirm that their
conjecture is true (for connected subcubic graphs with more than $70$
vertices). Our result is sharp due to the existence of subcubic graphs that are
not $(1^2,2^3)$-packing edge-colorable.
