Geometric Design Manual by Ethiopian Roads Authority

INTRODUCTION

1.1 General
Geometric Design is an essential component in the design development of a highway. This
Geometric Design Manual is prepared under the direction of the Ethiopian Roads Authority
to establish basic design techniques for economical design of highway geometric including
typical sections, horizontal and vertical alignment, and design of junctions. It is intended for
use in the design of all roads in Ethiopia.

1.2 Purpose
ERA has initiated a comprehensive program to rehabilitate, upgrade and expand the highway
network in Ethiopia. To plan and implement the program in a coherent way, using modern
standards and technology, ERA decided to establish a uniform framework. Developing a
Geometric Design Manual was part of this framework.
The purpose of this design manual is to give guidance and recommendations to the engineers
responsible for the geometric design of roads in Ethiopia.

1.3 Scope
The procedures for the geometric design of roads presented in this manual are applicable to
trunk roads, link roads, main access roads, collector roads, feeder roads and unclassified
roads as defined by ERA in this Geometric Design Manual.
The use of the procedures described in this manual should help in achieving reasonable
uniformity in geometric design for a given set of conditions.

1.4 Organization of the Manual

The overall organization of this manual and of the design process are as follows.
After this introduction, a summary of the standards developed within the manual together
with departures from standards and the method of dealing with departures from standards,
are given in Chapter 2.

Chapter 3 deals with preliminary design considerations. Specifically, it lists procedures for
identification of potential alignments in the route corridor selection process and Chapter 4
discusses survey requirements.

This Geometric Design Manual-2002 is one of the series of “Design Manuals, Standard Contract Documents and Specifications” prepared under a credit financing of the International Development Agency (IDA). The consulting services were provided by the Louis Berger Group, Inc.