"Вперед, бабушка и дедушка!"
What does 'allez opi-omi' mean?
The sign is a combination of two languages, French and German. "Allez" means "go" in French, according to Google Translate, while "opi" and "omi" are German terms for "grandpa" and "grandma," according to
Dict.cc. So the sign would translate to "Go grandpa-grandma."