Watch the Interstate Blues: Rhythm 1 online guitar lesson by Andy Aledort from Jam Night Vol. 2
This "Key to the Highway" type chord progression can be thought of as two distinct four-bar forms that are joined together: the first four-bar form features one bar of the I (one) chord, A, followed by one bar of the V (five) chord, E, followed by two bars of the IV (four) chord, D. In the second four-bar form, a single bar of the I chord is followed by a single bar of the V chord, and then the eight-bar form concludes with a standard two-bar turnaround of six beats of the I chord followed by two beats of the V chord. For most of the previous song examples, I have started with a "bed" rhythm track built mostly from lower voiced chords for the first rhythm example, and then added a higher "supplemental"-type part for the second rhythm example. For this tune, I prefer to start with a more complex rhythm part, one that is built from shifting triads played high on the fretboard, played in conjunction with single-note melodic phrases. My reasoning is that this single rhythm part will sound great if one were performing the song in a solo context, in that it has a lot of activity but it is still relatively easy to sing over while also playing.