SR2 ECE R66 typically refers to a specific bus model—the Laksana Legacy SR2 —notable for its compliance with the
Most people focus on side skins. However, in a rollover, the is the first contact point. If the roof skin is thin or poorly bonded, the roof bows will buckle sideways. An SR2 R66 roof skin must be at least 1.2mm steel (or equivalent) with anti-buckling corrugations.