uk a blackwall tunnel tidal flow stopped as per the header the tidal flow has been stopped in that east london england tunnel i removed the entry from the article as there is no section for defunct counter flow systems the original entry is as follows the a blackwall tunnel x lane tunnels in the morning lanes used for northbound towards the city centre traffic lane for southbound traffic in the evening lanes are provided in both directions this counterflow system was permanently stopped on april with reasons given as increased dangereous driver behavior see blackwall tunnel article for citations and references