[Imp]

This is hard thing to code as I think the AI looks at units individualy rather than the tactical picture.
I agree has a tendency to rush head long to destruction but sometimes it does otherwise.
Slows to what I call combat speed or becomes stationary or a combination of the two.
Nearing victory hexes seems to modify behaviour in my opinion causing slowing/unloading.
If possible perhaps something like a check to see if any freindly units within XX range have been fired on or wrecked.

Other possible option would be the ability to "crosstag" formations.
Assign tank formation to infantry formation & it trys to shadow & support with the usual randomness thrown in.
Serious work if possible I would think as picklists would need to factor in the ability at purchase for the AI to decide which if any formations its going to mate.

Trouble is again so many variables you cant just set vehicles to move slow sometimes you want the speed otherwise it would not be a factor in vehicle design.