Overall admission rate does not mean that your chance of admission is that chance.
A safety is a college that is 100% likely to admit you in particular.
Note that many colleges have different admission selectivity for different majors, or for in-state and out-of-state students. For example, University of Texas - Austin automatically admits Texas students in the top 6% of their class, which fills up about three quarters of the class (these students can consider it a safety if they are not applying to a competitive major). All out-of-state (including international) students and Texas students outside of the top 6% compete for the small number of remaining places, so all such students should consider it a reach.