Which statement about prohibiting or restricting road traffic and measures to ease congestion is NOT correct?

1. ①Even when traffic is prohibited or restricted, there is no need to give public notice of it.
2. ②If deemed necessary, the commissioner of a metropolitan/provincial police agency may designate a section and prohibit or restrict the passage of pedestrians, vehicles or trams.
3. ③A police station chief may first prohibit or restrict traffic and then consult the road manager to set the targets, section and period.
4. ④A police officer may take necessary measures to ease congestion when traffic is backed up and serious congestion is clearly feared.