Besides checking that it is safe, for at least how many seconds must you signal before moving out from the kerb into traffic?

Check mirrors, blind spots and the gap, and give way to traffic already in the lane. Other signalling situations have their own requirements.

同时检查镜子和盲点，并给原车道车辆让行。该数字针对题述动作，不应忽略其他场景的具体示意规定。