Existing traffic on the Traffic Instructions window can be completely erased by clicking the Erase 
button on the tool bar.
The difference between the Erase feature and the Delete 
button is that Erase removes all the existing instructions but retains the internal traffic ID that identifies the traffic record as belonging to this media. It performs the same function as manually deleting each row of traffic line by line and is the equivalent of clearing the work space and starting over. The record of the previous traffic (if any) is also maintained, which still permits reverting to the previous traffic for the media.