材料：
Coastal conditions
The area described in the volume presents the mariner with a generally adverse combination of navigational factors which are outline below．
Local Topography．The Dover Strait is shallow and only is 18 miles wide at its narrowest point．Passage through the strait is further constricted by a series of narrow banks，running NE-SW．The seabed is also littered with wrecks．
Natural Conditions．There are strong tidal streams in the strait．Sea level may differ from that predicted and in particular may be lower than expected due to negative tidal surges．The area is also subject to gales and poor visibility．
Risk of Collision．There is a high risk of collision caused by the density of vessel traffic on passage through the strait，including deep-draught vessels，and crossing traffic，including ferries and high speed craft．
Mine danger area There are two areas off the N coast of France，which remain dangerous because of mines lied in the war of 1939-1945．Due to the lapse of time the risk to surface navigation is now considered to be no more dangerous than that the ordinary risks of navigation but a very real risk still exists with regard to anchoring，fishing or any form. submarine or seabed activity．
问题：
The crossing traffic in the Dover Strait is probably running ________．