How do they change the number of lanes at the golden gate bridge?

Question

do they do it manually? and what time of the day do they do it? do they have to hold traffic and put up the yellow lane markers?

Answer 1

I would assume they close the bridge off for 2-3 minutes in order to make the change.  It would be too dangerous to do it when there are cars on it.

Answer 2

They draw more lines duh!