Is it legal?
 

to drive with the back hatch top half back window open?

today when driving i saw two cars do it and wondered. and no, they were not carrying any cargo that were oversized that required them to do so.

Don't think it illegal.Its not a good idea because the exhaust fumes will get sucked back into the vehicle,not sure if they have their side windows open if it'll gas the driver/passenger still.

I take you are refering to something like a 4Runner that has a rear window that can be rolled down. Old station wagons etc....

If so yes it is legal.... There is nothing that I am aware of in the MVA that would prohibit this.

But driving with a lift gate or sliding door open is illegal.

The way I interpret what he wrote, it is either a 92-95 style Civic hatchback where the glass folds up while the door is still closed.
Or an 89-93 style 240SX where the hatch is left open.

Just watch out for exhaust gas entering the passenger compartment because it is open. My Suburban owner's manual told me not to.

I would suspect that they are also ok.... as long as only the window portion opens I can not think of a law that prohibits this.... Kind of like a rear window in a pick up or the cadilc where the entire back of the cab opens.

if the glass sticks out too far doesn't that count as something that has to be flagged (similar to having a ladder stick out the back). whats the length/distance requirement for that