in texas the leo issue tickets to people who hang out the left lane. its a well known fact that the left lane on interstates, is for passing only except in special circumstances, or city traffic.
a driver should use common sense. driving too slow or too fast just screws up traffic flow.
drive at a reasonable rate of speed that does not impede traffic. use the truck lanes as much as possible, because these are for slower moving vehicles.
as clint eastwood says, be aware of your surroundings.