IF you do then you may want to change for your safety.
With the window partly down in a "T" bone /side impact crash on the passenger side the 3 point belt will not restrain you IN AN UPRIGHT POSITION and you will whiplash back and the side of your head will come into contact with the top edge ( a heavy impact onto a small surface area) with potentially permanent injuries or life endangering concequences.
The same thing will result in the event of driver side impact SO have the window ALL the way down OR no more than say 1/4 of the way open for ventilation.
FWIW over here the Ambos and Fireies call it "suicide glass"
With the window partly down in a "T" bone /side impact crash on the passenger side the 3 point belt will not restrain you IN AN UPRIGHT POSITION and you will whiplash back and the side of your head will come into contact with the top edge ( a heavy impact onto a small surface area) with potentially permanent injuries or life endangering concequences.
The same thing will result in the event of driver side impact SO have the window ALL the way down OR no more than say 1/4 of the way open for ventilation.
FWIW over here the Ambos and Fireies call it "suicide glass"