Four-level Stack
The four-level stack (or simply four-stack) has one major road crossing another on a bridge, with connector roads crossing on two further levels. This type of interchange does not usually permit U-turns. Interestingly, the four-level stack creates two "inverse" dual-carriageways—the turn ramps crossing the middle section have traffic driving on the opposite side of oncoming traffic to usual (see diagram for clarity).
Read more about this topic: Stack Interchange
Famous quotes containing the word stack:
“What is a farm but a mute gospel? The chaff and the wheat, weeds and plants, blight, rain, insects, sun—it is a sacred emblem from the first furrow of spring to the last stack which the snow of winter overtakes in the fields.”
—Ralph Waldo Emerson (1803–1882)