Notwithstanding the foregoing provisions of this chapter, every driver of a vehicle shall exercise due care to avoid colliding with any pedestrian upon any roadway and shall give warning by sounding the horn when necessary and shall exercise proper precaution upon observing any child or any obviously confused or incapacitated person or a person wholly or partially blind, carrying a cane or walking stick white in color, or white tipped with red or accompanied by a guide dog, upon a roadway.