Turnaround (road)

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In the field of road transport, a turnaround is a type of junction that allows traffic travelling in one direction on a road to efficiently make a U-turn (to reverse course and travel the opposite direction) typically without backing up or making dangerous maneuvers in the middle of the traffic stream. While many junction types permit U-turns, the term turnaround often applies to road junctions built specifically for this purpose.

[edit] Junction types designed specifically for U-Turns

The following road junction types are designed specifically to allow U-Turns.

The Texas U-turn allows traffic travelling on one direction of a one-way frontage road, running parallel to a highway, to cross the highway (via a grade separation) and turn onto the other frontage road, traveling in the opposite direction. The term refers to roadworks which are specially built for this purpose; and does not refer to use of an intersecting roadway to navigate between frontage roads.^[1]

The Michigan left allows traffic travelling in one direction on a divided highway (typically one with traffic lights and at-grade intersections) to perform a U-turn through the median.

A cul-de-sac allows a smooth turnaround at the end of a dead end street.

Sometimes, a modified reverse jughandle is used to permit U-turns. Traffic wishing to turn around executes a left turn (across oncoming traffic) onto the jughandle, but rather than merging onto a crossing road, the jughandle turns back and merges into the road just left, in the opposite direction. An example of this can be found on a divided section of U.S. Highway 101 south of Lincoln City, Oregon. ^[2]

[edit] Junction types which permit U-Turns

The following junction types typically permit U-turns but are not designed specifically for that purpose.

Normal at-grade intersections on divided highways often allow traffic travelling on the divided highway to perform a U-turn, often when there is a green light for traffic turning onto the side road, crossing the opposing lanes (left turns in countries where traffic moves on the right; right turns in countries where traffic moves on the left).

Traffic circles and roundabouts make turning around rather easy.

Many freeway interchanges with surface streets are configured so that traffic on the freeway can exit onto the surface street, and re-enter the freeway in the opposite direction.

The cloverleaf interchange permits turning around by navigating two consecutive "leaves" of the clover pattern.

edit Types of road junctions
Interchanges (grade separated)	Cloverleaf - Diamond - Directional T - Diverging diamond Parclo - Trumpet - SPUI - Stack - Three-level diamond - Raindrop
Intersections (at-grade)	Box junction - Continuous flow - Hook turn - Jughandle - Michigan left Quadrant roadway - Roundabout - Superstreet - 3-way junction - Traffic circle - Bowtie