If you consider motion unfolding on a map of landmarks fixed with respect to a single inertial reference frame, the map-frame choice defines both distances and simultaneity! The two times in the metric equation (

As a result, invariance in relativity as it differs from Newtonian
physics can be described clearly, and tons of problems including
constant acceleration can be worked, *before* inertial frames
in relative motion (with length-contraction, velocity-addition,
and frame-dependent simultaneity) need be considered quantitatively.
The study of relative motion also simplifies when the
variables defined above are put to use.

While at it, should you consider accelerated motion of a traveler on the map using clocks in a chase-plane not quite keeping up with the traveler, one can also find a context in which Galileo's 1-D constant acceleration equations provide relativistically correct predictions as well. In fact, Galileo discovered

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`Version release date: 12 Apr 2005.`

Information on applications, and on related publications, are listed in our Map-Based Relativity Table-of-Contents. Send your thoughts and suggestions via e-mail to philf@newton.umsl.edu.