While driving tank as driver - there is no issue.
While driving tank as driver and you got one more tank under command - while performing braking, second tank will not stop.
While sitting in tank as commander and ordering your tank to move, then to stop - you can watch "Altis Drift" showcase - no grip to surface, tank is braking just like on the icefield.
All this is resoult, of Ai driver of ANY tracked vehicle cannot stop it properly - Player driver by pusing S key is stopping vehicle diferent (there is grip between tracks and surface) than AI (where there is almost no grip) - so we got issues where support (tracked apc with ammo, tank support or whatever you call) is killing the caller and his squad as they cant stop the vehicle in front of the player.
Here is quick video (3 minutes) describin issue very detailed