Based on college sophomore-level knowledge, we developed [1] a description of special relativity (SR) that applies to accelerated, and arbitrary, motion.
This discussion considers, although not regularly offered at sophomore-level, that general relativity (GR) gives a better basis in undergraduate courses, and can be derived using [1].
This is useful because GR underlies much of the contemporary understanding of modern physics, including the big bang, pulsars, quasars, and gravitational waves.
As shown in [1], the laws of SR are just often simpler when they work in-between inertial frames, as originally stated.
[1] Preprint Special Relativity Applied to Arbitrary Motion