Effect of Design Speed in Radius of Horizontal Curves and K of Vertical Curves

Two crucial transitional components in roadway engineering designs are horizontal and vertical curves. The design of these curves is influenced by various elements, the most significant of which is friction, as well as the road's design speeds. In order to give cars on the road a steady rate of revolution, horizontal curves are described as semicircles. The centrifugal force rules of physics are used to calculate the radii of horizontal curves. When a turn is narrower (has a smaller radius) than when it is wider (has a bigger radius), the centrifugal force is higher. Lateral friction (fs) functions as a force opposing the centrifugal force while the vehicle is driving on a level surface, although it often offers relatively little resistance, necessitating a very large circle for the vehicle to spin on the level. Although the purpose of using a vertical curve is to alter the highway's contour to create a seamless transition between two halted ramps, the vertical curve's design is dependent upon the road's planned design speedIn light of the aforementioned, the study sought to determine the nature of the relationship between design speed and various design criteria, including stopping sight distance (SSD), length of the radius of curvature (R), horizontal sight line displacement (HSO), braking distance (db), maximum span (emax), vertical curvature, lane and shoulder width (L), maximum lateral friction coefficient (fmax), as well as the relationship between speed and various engineering design elements, including track width, the relationship between the inferred design speed and the specified design criteria for horizontal and vertical curves. The design speed and the radius of horizontal curves were shown to be positively correlated. To attain the highest level of safety on roads with vertical curves, it is vital to ascertain the value of K while calculating the design speed in both sag and crest vertical curves.