Things That the Cane May Not Detect: Overhanging Obstacles
Overhanging obstacles, such as tree branches, and signs or objects that protrude from walls or poles are not detected by the cane.
Eelectronic travel aids can be very useful for detecting these obstacles.
Many people wear glasses and/or a brim hat to prevent injury from tree branches or other overhanging objects, and some even use an umbrella to give them advance warning.
If such a hazard is expected, the blind traveler can use a modified upper hand and forearm technique to protect the head (as shown in the last photo below).
Photos below (from left to right) show a display umbrella; a sign that was tilted over the sidewalk; and a pole with a railroad crossing sign left by a construction crew. These each protrude where the cane will not detect them, and are hazards.