outrider

1. N-COUNT Outriders are people such as police officers who ride on motorcycles or horses beside or in front of an official vehicle, in order to protect the people in the vehicle. 摩托卫队; 护卫马队[usu n N]

...a black Mercedes with motorcycle outriders provided by the city's police. ...一辆黑色奔驰车和由该市警方提供的摩托卫队。