# Transportation Highways Horizontal Curve Calculator

This calculator allows you to perform horizontal curve calculations used in highway engineering. In road design, highway engineers often consider various parameters to determine how much horizontal curves should be.

This calculator allows you to perform horizontal curve calculations used in highway engineering. In road design, highway engineers often consider various parameters to determine how much horizontal curves should be. This calculator calculates an appropriate horizontal curve radius and other relevant values based on specific input data.

When using the Online Transportation Highways Horizontal Curve Calculator you can calculate by entering: Intersection Angle, Degree of Curve and Point of Intersection.

Table of contents:

## How to Calculate the Horizontal Curve of Transportation Highways?

The following steps are generally followed when calculating the horizontal curves of transportation highways:

**Determination of Road Design Parameters:**As a first step, the parameters required for the design of the road are determined. These parameters include road width, speed limits, other features on the road and topographical features of the road.**Investigation of Road Geometry:**Factors such as existing topographic conditions, slopes and curves along the route of the road are examined. A suitable road geometry is determined by taking into account the geological and topographical features of the area where the road will pass.**Determination of Horizontal Curve Radius:**In accordance with the determined road geometry, the radius of the horizontal curve is calculated. This calculation is based on factors such as speed limits, maneuverability and safety of vehicles.**Drawing and Construction of the Road:**Based on the calculated horizontal curve parameters and other design features, the road is planned and constructed. It is ensured that the horizontal curves are properly marked and necessary measures are taken for the safety of the road.

These steps are standard methods used in highway engineering and are important in road design to create a safe and effective road geometry.

### What is a Horizontal Curve?

A horizontal curve is a curve formed when a transportation line, such as a road or railway, deviates or turns from a straight line. In a linear section along the route of the road, a horizontal curve changes the direction of the road, whereas in a straight line, a horizontal curve moves in line with the direction in which the vehicle is moving. Horizontal curves are where bends or curves in the road occur.

These curves are determined by the natural topography and intended use of the road and ensure that the road can be used safely and efficiently. Horizontal curves play an important role in road design and their proper planning and marking is critical for traffic safety.

### Horizontal Curve Types

The types of horizontal curves vary depending on the shape of the road and the turning characteristics. Here are some common types of horizontal curves:

**Circular Curves:**These curves have a constant radius and curve in a circular shape. Most roads are usually designed with circular curves.**Parabolic Curves:**These curves are similar to circular curves, but their radius is not constant. They are used in the design of more complex roads.**Combined Curves:**A combination of circular and parabolic curves. Part of a given curve is circular and the other part is parabolic.**Spiral Curves:**These curves are a type of curve in which a radius is constantly changing. This is used to smoothly change the speed and movement of vehicles.**Composite Curves:**These are complex types of curves where more than one type of curve is combined. They are especially used in the design of complex roads.

These types of horizontal curves are selected depending on the topographical characteristics of the road and the intended use of the road, and ensure safe and efficient use of the road during the design process.

### Horizontal Curve Parameters

Horizontal curve parameters are values that define the geometric characteristics of a curve section on a road. These parameters are set to ensure that the road can be used safely and effectively. Here are some commonly used horizontal curve parameters:

**Horizontal Curve Radius (R):** An important measure of the curvature of the road. The horizontal curve radius is the distance from the center of a curve to the horizontal surface of the road. A larger radius means less curvature and a slower turn.

**Horizontal Curve Length (L):** The total length of the curved section of the road. It varies depending on the turning angle and radius of the road.

**Horizontal Curve Intersection Angle (Î”):** The angle at which the curved section of the road turns. The horizontal curve intersection angle determines the degree of curvature of the road.

**Horizontal Curve Slope (Î¸):** The slope or grade of the curved section of the road. The slope of the road allows vehicles to turn safely.

**Horizontal Curve Turn Ratio (ROR):** A parameter that determines the turning characteristics of the road. It is the ratio of the radius of the horizontal curve to the width of the road.

These parameters play an important role in road design and safety analysis, and their proper determination ensures safe and efficient use of the road.

### Transportation Highways Horizontal Curve Calculation Example

When designing a highway, we want to calculate the horizontal curves of a particular road section. This road section contains a curve that starts with a straight section and ends with a turn. The straight section is 300 meters long and the turn is at an angle of 90 degrees. Let’s calculate the radius of the horizontal curve of the road and other relevant parameters.

Solution

**Horizontal Curve Radius (R) Calculation:**

The radius of the horizontal curve is calculated by dividing the path by the angle of rotation in the section where the turn is made.

Î¸ = 90 degrees (turning angle)

L = 300 meters (straight section length)

R = L / Î¸

R = 300 / 90

R â‰ˆ 3.33 meters

**Horizontal Curve Length (L) Calculation:**

The horizontal curve length is calculated depending on the rotation angle and the horizontal curve radius.

L = R * Î¸

L = 3.33 * 90

L â‰ˆ 300 meters

**Horizontal Curve Intersection Angle (Î”) Calculation:**

The horizontal curve intersection angle is equal to the angle at which the turn is made.

Î” = 90 degrees

In this example, we have calculated a horizontal curve with a given straight section and a turn. Important parameters such as horizontal curve radius, horizontal curve length and intersection angle must be determined for road design and safety.