Horizontal Curve Design and Signing

Section A. Signing Guidelines

TxDOT Project 5-5439: Texas Roadway Analysis and Measurement Software (TRAMS): Procedures for Installing Software and Device Drivers.  M. Pratt and J. Bonneson. This document describes the procedures to install TRAMS and the device drivers on a personal computer. The procedures apply to Windows XP Service Pack 2 or newer. TRAMS uses a GPS receiver to measure horizontal curve radius and an electronic ball-bank indicator to measure superelevation rate.  REPORT  TRAMS INSTALL

TxDOT Report 5-5439-01-1: Workshops on Using the GPS Method to Determine Curve Advisory Speeds. M. Pratt, J. Miles, and J. Bonneson. This document describes the GPS Method and the research undertaken to develop it. The GPS Method was found to provide curve advisory speeds that are more uniform and consistent than other methods. A series of workshops were conducted to describe the use of the GPS Method. The findings from the workshop are summarized.  REPORT 

TxDOT Report 0-5439-P1: Horizontal Curve Signing Handbook. J. Bonneson, M. Pratt, J. Miles, and P. Carlson. The procedures described in this handbook are intended to improve consistency in curve signing and driver compliance with the advisory speed. The handbook describes guidelines for determining when an advisory speed is needed, criteria for identifying the appropriate advisory speed, an engineering study method for determining the advisory speed, and guidelines for selecting other curve-related traffic control devices.  REPORT   SPREADSHEET  Supplemental Report 

TxDOT Report 0-5439-1: Development of Guidelines for Establishing Effective Curve Advisory Speeds. J. Bonneson, M. Pratt, J. Miles, and P. Carlson. This document summarizes the research conducted and the findings from a two-year investigation of driver behavior on horizontal curves on rural two-lane highways. The findings from the research were used to develop criteria for setting the curve advisory speed, a method for determining this speed, and guidelines for identifying appropriate curve-related traffic control devices.  REPORT 

Section B. Design Guidelines

NCHRP Project 15-16: Superelevation Distribution Methods and Transition Designs, Final Report. J. Bonneson. The objective of this research was to evaluate and recommend revisions to the horizontal curve design guidelines presented in the 1994 AASHTO publication A Policy on Geometric Design of Highways and Streets (i.e., the Green Book). This evaluation was based on a review of current practice, a review of the research literature, and an analysis of alternative guidelines and design control values. The evaluation required the development and calibration of several theoretic models. These models were calibrated using field data collected at 55 curve study sites.  REPORT