DefinePK

Abstract

The establishment of figures on the ground is an important task of the field surveyor, not only in engineering construction but also in cadastral surveying. It is a relatively easy task to peg out the boundary of a rectangular concrete slab, but considerably more difficult to establish the location of points along an elevated curved highway. Thus Radii measurements are important for many reasons such as: Setting curve advisory speeds; predicting vehicle operating speeds; Spacing curve delineation treatments such as post-delineators<i>, </i>chevrons, and raised retro reflective pavement markers; performing highway safety audits; and evaluating traffic crashes. Many groups, including transportation agencies, accident investigators, and transportation researchers, would find an accurate, quick, and safe method to estimate the radius of horizontal curves particularly useful. The present work explains the ten methods of estimating radius; a) Basic ball bank indicator (BBI), b) Advanced BBI, c) Chord length, d) Compass, e) Field survey, f) Global Positioning System (GPS) unit, g) Lateral acceleration, h) Plan sheet, i) Speed advisory plate and j) Vehicle yaw rate. Also each method was programmed as a software named RET (Radius Estimating Techniques). It represent of a collection of subroutines for each method. This program is written in Mathematical Computer Aided Design language (MCAD). It also includes a subroutine written in Visual BASIC language for calculating the super elevation of a designed or existing horizontal curves.