1. An automotive vehicle comprising:a vehicle body having a fore portion, and an aft portion, and a longitudinal axis extending from the fore portion to the aft portion;
a rocker inner panel comprising a first channel with an interior side and an exterior side, the interior side being secured to the vehicle body, the first channel comprising a first upper horizontal sidewall, a first lower horizontal sidewall, and a first vertical endwall coupling the first upper horizontal sidewall to the first lower horizontal sidewall at the interior side; and
a rocker outer panel secured to the rocker inner panel, the rocker outer panel comprising a second channel, a third channel, and a fourth channel, the second channel being secured to the third channel, the third channel being secured to the fourth channel, an upper cavity being defined between the second channel and the third channel, an intermediate cavity being defined between the third channel and the fourth channel, and a lower cavity being defined between the second channel and the third channel,
wherein the first channel includes a first lower flange and the fourth channel includes a fourth lower flange, the first lower flange being secured to the fourth lower flange.