Origin
Before the mid 1980s, Pittsburgh had a non-standard traffic light sequence. The green light would become simultaneous green/yellow, then just yellow, and finally red. While some believe this sequence reduced the chances of cross-traffic running the red light immediately before the anticipated green, and thus encouraged early left turning, this practice is also observed in other regions with no history of simultaneous green and yellow. Some large intersections have four-way red for several seconds as a safety buffer, providing an opportunity for an illegal and unsafe left turn after cross-traffic has physically stopped but before the green light gives legal right of way.
Read more about this topic: Pittsburgh Left
Famous quotes containing the word origin:
“Someone had literally run to earth
In an old cellar hole in a byroad
The origin of all the family there.
Thence they were sprung, so numerous a tribe
That now not all the houses left in town
Made shift to shelter them without the help
Of here and there a tent in grove and orchard.”
—Robert Frost (1874–1963)
“All good poetry is the spontaneous overflow of powerful feelings: it takes its origin from emotion recollected in tranquillity.”
—William Wordsworth (1770–1850)
“Our theism is the purification of the human mind. Man can paint, or make, or think nothing but man. He believes that the great material elements had their origin from his thought.”
—Ralph Waldo Emerson (1803–1882)