Editing Cloverleaf interchange (section)

== Overview ==
[[File:Flyover1.jpg|thumb|A cloverleaf interchange near [[Sharjah International Airport]] in the [[United Arab Emirates]], {{coord|25.298611|n|55.593611|e}}]]
Cloverleaf interchanges, viewed from overhead or on maps, resemble the [[leaf|leaves]] of a [[four-leaf clover]] or less often a 3-leaf clover.
In the [[United States]], cloverleaf interchanges existed long before the [[Interstate highway|Interstate system]].  They were originally created for busier interchanges that the original [[diamond interchange]] system could not handle.  Their chief advantage was that they were free-flowing and did not require the use of such devices as [[traffic signals]]. This not only made them a viable option for interchanges between [[freeways]] (where such devices are typically not an option), but they could also be used for very busy [[arterial (road)|arterials]] where signals could present congestion problems.

They are common in the United States and have been used for over 40 years as the [[Interstate Highway System]] expanded rapidly. One problem is that, frequently, large [[truck]]s exceeding the area [[speed limit]] roll over.<ref>{{Cite book|title = Improved Safety Information to Support Highway Design, Issue 430|last = Peter|first = Ronald| publisher = Transportation Research Board|year = 1999|isbn = 0-309-06608-5|location = Barnes&Noble.com|pages = 96}}</ref>  Another problem is the merging of traffic ([[#Problems|see below]]). For these reasons, cloverleaf interchanges have become a common point of traffic congestion at busy junctions.

[[At-grade intersection|At-grade]] cloverleaf configurations with full four leaves and full outside slip ramps are extremely rare, though one exists in [[Toms River, New Jersey]].<ref>[http://maps.google.co.uk/maps?q=1201%20Hooper%20Avenue%2C%20Toms%20River%2C%20New%20Jersey%2C%20United%20States&um=1&hl=en&ie=UTF-8&sa=N&tab=wl Google Maps<!-- Bot generated title -->]</ref> Any other intersection with merely one, two, or three leaf ramps with outer ramps would not be designated a "cloverleaf" and simply be referred to as a [[jughandle]] or parclo intersection.