Many colleges + universities do require subject tests (often two), although some let you substitute the ACT for subject tests. But which subjects are required will depend on the school, your intended major, etc. Math 1 or 2 is a common requirement for engineering, science, or other technical major. For example, see:
Ivy West: SAT Subject Tests Requirements
Sometimes, people that don't do all that well on regular SAT math but do fine on the SAT IIs level 1, the two tests are somewhat different.