In what area of the windows are stickers or signs allowed?

Stickers or signs are permitted in the lower 7-inch square area of the vehicle windows because this specific area is designed to be less obstructive to the driver's view. By limiting placements to this section, regulatory bodies ensure that the driver's line of sight is not impeded, which is crucial for safety while operating the vehicle. This regulation helps maintain visibility for the driver and reduces distractions that can arise from excessively cluttered windows, particularly in crucial viewing areas like the front windshield. While other options may imply that stickers can be placed more liberally, they do not prioritize safety and visibility standards as effectively as the designated lower section does.