Road curves are irregular bends in
roads
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
to bring a graduation change of direction. Similar curves are on
railways
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...
and
canals
Canals or artificial waterways are waterways or river engineering, engineered channel (geography), channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport watercraft, vehicles (e.g. ...
.
Curves provided in the horizontal plane are known as horizontal curves and are generally circular or parabolic. Curves provided in the vertical plane are known as vertical curve.
Five types of horizontal curves on roads and railways:
* Simple curve
* Compound curve
* Transition curve
* Reverse curve
* Deviation curve
Two types of vertical curves on roads:
* Valley curve
* Summit curve
Horizontal Curve
Simple curve
![Curve 2014-08-18 12-57](https://upload.wikimedia.org/wikipedia/commons/4/4c/Curve_2014-08-18_12-57.jpg)
A simple curve has the same
radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
throughout and is a single
arc of a
circle
A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is const ...
, with two
tangent
In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve. More ...
s meeting at the intersection (B in this diagram).
Compound curve
![Road curve 2014-08-18 12-16](https://upload.wikimedia.org/wikipedia/commons/6/6e/Road_curve_2014-08-18_12-16.jpg)
A compound curve has two or more simple curves with different radii that bend the same way and are on the same side of a common tangent. In this diagram, MN is the common tangent.
Reverse curve
![Curve 2014-08-18 12-52](https://upload.wikimedia.org/wikipedia/commons/5/5d/Curve_2014-08-18_12-52.jpg)
Also called a serpentine curve, it is the reverse of a compound curve, and two simple curves bent in opposite directions are on opposite sides of the common tangent.
Deviation curve
![Curve 2014-08-18 12-19](https://upload.wikimedia.org/wikipedia/commons/b/bd/Curve_2014-08-18_12-19.jpg)
A deviation curve is simply a combination of two reverse curves. It is used when it is necessary to deviate from a given straight path to avoid intervening obstructions such as a building, a body of water, or other significant site.
Transition curve
Is a curve with a gradual change in elevation on the outside of the curve to help drivers comfortably take turns at faster speeds
Vertical road
Valley curve
Also called a sag curve, this curve dips down and then rises back up. These are placed in the base of hills. The opposite of summit curve.
Summit curve
Also called the crest curve, this curve rises and then dips down. At the peak of hills. The opposite of valley curve.
See also
*
Geometric design of roads
The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficienc ...
*
Hairpin turn
A hairpin turn (also hairpin bend or hairpin corner) is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn about 180° to continue on the road. It is named for its resemblance to a bent metal hai ...
*
Ranging rod
A ranging rod (or range rod) is a surveying instrument used for marking the position of stations, and for sightings of those stations, as well as for ranging straight lines. Initially these were made of light, thin and straight bamboo, or of well ...
s
*
Survey camp
Survey Camp is an army tradition that was discontinued in the later part of twentieth century but was reinstated in 2002 across the universities of the world with a whole new structure. It is the civil engineering training course for two weeks usu ...
*
Tape (surveying)
A tape measure or measuring tape is a flexible ruler used to measure length or distance.
It consists of a ribbon of cloth, plastic, fibre glass, or metal strip with linear measurement markings. It is a common measuring tool. Its design al ...
*
Transition curve
Transition or transitional may refer to:
Mathematics, science, and technology Biology
* Transition (genetics), a point mutation that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine (C ↔ ...
References
*
Surveying
Civil engineering
{{road-stub