lollipop man
noun/ˈlɒlipɒp mæn/
/ˈlɑːlipɑːp mæn/
(British English, informal)- a man whose job is to help children cross a busy road on their way to and from school by holding up a sign on a stick telling traffic to stop
（手持车辆暂停牌以帮助学童穿越马路的）交通安全员