There are several consecutive s-curves on this mountain road, so drive with extra caution.

s-curves 是由字母 s 和名词 curve（弯道）组成的复合词。s 在这里形容弯道的形状像字母"S"一样蜿蜒曲折。s-curves 指"S形弯道"，即连续呈S形走向的弯曲路段。