Tidal Flow

Tidal Flow is a lane in which traffic may travel in either direction, depending on certain conditions. Typically, it is meant to improve traffic flow during rush hours, by having overhead traffic lights and lighted street signs notify drivers which lanes are open or closed to driving or turning.  The Tamar bridge runs over the River Tamar from near Wearde, Saltash in the west to Riverside, Plymouth in the east. It has a central span of 335 metres (1,099 ft) and two side spans of 114 metres (374 ft). It has a main span of three lanes, which use a tidal flow arrangement to maximise traffic flow at rush hour, and two outer lanes. The north of these is used as a local access route from Saltash, while the south is used by cyclists and pedestrians but could be converted to meet future vehicle demand if alternatives for pedestrians and bicycles were provided, a dedicated ferry, shuttle bus, cable car or bridge have been considered.   Entry to blackwall tunnel Blackwall Tunnels, London The Blackwall Tunnel only ran tidal flow in the AM peak period. Tidal flow was implemented at the discretion of the police. It was only usually implemented between 0630 and 0900 hrs, and only ran for as long as it took to reduce the queuing on the south side - run it for too long and the southbound traffic would begin to back up. During the morning peak, tidal flow could be implemnted up to three times, for as little as 20 minutes at a time. , a tidal flow system operated through the southbound tunnel, enabling three northbound lanes to operate across the river, with only one southbound lane available.  A102 northbound at blackwall tunnel