Editing Overpass (section)

==Highway and road==
In North American usage, a ''flyover'' is a high-level overpass, built above main overpass lanes, or a bridge built over what had been an [[at-grade intersection]]. Traffic engineers usually refer to the latter as a ''[[grade separation]]''. A flyover may also be an extra ramp added to an existing interchange, either replacing an existing [[cloverleaf interchange|cloverleaf]] loop (or being built in place of one) with a higher, faster ramp that eventually bears left, but may be built as a right or left exit.

A cloverleaf or partial cloverleaf contains some 270 degree loops, which can slow traffic and can be difficult to construct with multiple lanes. Where all such turns are replaced with flyovers (perhaps with some underpasses) only 90 degree turns are needed, and there may be four or more distinct levels of traffic. Depending upon design, traffic may flow in all directions at or near open road speeds (when not congested). For more examples, see [[Freeway interchange]].