The Grantee, upon making an opening upon any of the streets, alleys, or public ways of the City, for the purpose of laying pipes, and/or maintaining gas mains, shall use due care and caution to prevent injury to persons and shall replace and restore all public ways to their former conditions as nearly as practicable and within reasonable time, and shall not unnecessarily obstruct or impede traffic on streets, alleys and public ways of said City.