i don't install it on the windshield anymore. there's sort of a vent on my dash that'll hold my epass transponder while i pass the toll plaza. i put it in that area as i approach the toll plaza and put it back in its storage space afterwards. that position, though on the dash, is actually the best place for the epass tag to be, in my experimentation. i tried mounting it high on the the windshield, and sometimes it had a hard time getting a reading.