Separation of Flows
Some more recent implementations of reversible lanes use a movable barrier to establish a physical separation between allowed and disallowed lanes of travel. In some systems, a concrete barrier is moved during low-traffic periods to switch a central lane from one side of the road to another; some examples are the five lane San Diego-Coronado Bay Bridge in San Diego, California, the seven lane Tappan Zee Bridge on the Hudson River in New York and the eight lane Auckland Harbour Bridge across the Waitemata Harbour in Auckland, New Zealand. Other systems use retractable cones or bollards which are built into the road, or retractable fences which can divert traffic from a reversible ramp. The two center lanes of the six-lane Golden Gate Bridge are reversible; they are southbound during morning rush hour and northbound at evening rush hour, and are demarcated by vertical yellow markers placed manually in sockets in the roadway.
Many urban freeways have entirely separate carriageways (and connecting ramps) to hold reversible lanes (the reversible lanes in such a configuration are often referred to as "express lanes"). Generally, traffic flows in one direction or another in such a configuration (or not at all); the carriageways are not "split" into two-lane roadways during non-rush periods. Typically, this sort of express lane will have fewer interchanges than the primary lanes, and many such roadways only provide onramps for inbound traffic, and offramps for outbound traffic.
Read more about this topic: Reversible Lane
Famous quotes containing the words separation of, separation and/or flows:
“... the separation of church and state means separation—absolute and eternal—or it means nothing.”
—Agnes E. Meyer (1887–1970)
“Like sleep disturbances, some worries at separation can be expected in the second year. If you accept this, then you will avoid reacting to this anxiety as if it’s your fault. A mother who feels guilty will appear anxious to the child, as if to affirm the child’s anxiety. By contrast, a parent who understands that separation anxiety is normal is more likely to react in a way that soothes and reassures the child.”
—Cathy Rindner Tempelsman (20th century)
“All things change, nothing is extinguished.... There is nothing in the whole world which is permanent. Everything flows onward; all things are brought into being with a changing nature; the ages themselves glide by in constant movement.”
—Ovid (Publius Ovidius Naso)