Note: Must be ambulance on emergency mission (answer 2), in case just ambulance (answer 3) alone is not enough.
Fire truck, dyke protection vehicle, police vehicle, military vehicle; organized parade procession.
Fire truck, military vehicle, police vehicle, ambulance on emergency duty, dyke protection vehicle, convoy led by police, car to work the task of overcoming natural disasters, epidemics or vehicles on duty in an emergency as prescribed by law.
Fire truck, military vehicle, police vehicle, ambulance, dyke protection vehicle, convoy led by police: organized marching convoy, hearse convoy, vehicle on task of troubleshooting natural disasters as prescribed by law.