Temporarily closing off the downtown streets for a more walkable experience, more diverse shopping alternatives and the loitering problem ranked high in a new survey of Nevada City residents.The survey, led by the Nevada City Chamber of Commerce, was revealed to citizens during a meeting Monday night. Nevada City has never conducted such a study seeking residents' opinions, and it is vital because of the flagging local and national economy, said Kirk Valentine, head of the chamber's marketing committee and owner of the Nevada City Classic Cafe."The most astounding survey result is the numbers favoring closing off the streets," Valentine …