Sight obstructions: Nothing herein provided shall be construed as permitting any obstruction to view which may constitute a traffic hazard. On the contrary, it shall be unlawful for any person to erect or place or cause to be erected or placed, or to perpetuate or maintain, on any property under his control any hedge, tree, shrub, or other growth or any fence or other structure in such manner or at such location as to constitute an obstruction to view creating a traffic hazard. On corners or on street curves of more than sixty (60) degrees, when doubt may exist regarding sight obstructions, the approval of the city engineer shall be required.