Geometric Design Manual-2002
Chapter 1 Introduction
1.
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 Authorit
Geometric Design Manual-2002
Chapter 13 Grade - Separated Junctions
13
GRADE SEPARATED JUNCTIONS
13.1 General The circumstances in which the use of a grade separated junction is warranted are usually as follows: An at-grade junction has insufficient capac
Geometric Design Manual-2002
Chapter 14 Safety
14
SAFETY AND MISCELLANEOUS DESIGN ITEMS
14.1 Introduction Road user safety has economic consequences in terms of property damage and loss of earnings or production resulting from physical injury, in addition
Geometric Design Manual-2002
Chapter 15 Road Furniture & Markings
15
ROAD FURNITURE AND MARKINGS
15.1 Introduction This chapter deals with road furniture and markings. These features include the elements intended to improve the driver's perception and com
Geometric Design Manual-2002
Appendix A Classification of Roads
A.
CLASSIFICATION AND DESCRIPTION OF ROADS The following are the classified roads in Ethiopia under the five classes. This classification should always be updated and the information should b
Geometric Design Manual-2002
Appendix B Classification of Roads
B.
COEFFICIENT OF FRICTION
The coefficient of friction as determined by studies is as shown in Figure B-1.
Figure B-1: Skid Resistance for Various Tire and Pavement Conditions
Ethiopian Roads
Geometric Design Manual-2002
Appendix C Measuring Sight Distance
C.
MEASURING AND RECORDING SIGHT DISTANCE ON PLANS
By determining graphically the sight distances on the plans and recording them at frequent intervals, the designer can appraise the overall
Geometric Design Manual-2002
Appendix D Utilities
D.
UTILITIES
D.1 Ethiopian Electric Light and Power Authority The Ethiopian Electric Light and Power Authority Distribution Manual, dated January 1975, shows the following parameters: Minimum vertical clea
Geometric Design Manual-2002
Appendix E Typical Cross Sections
E.
TYPICAL CROSS SECTIONS AND STANDARD CROSS SECTIONS
The desirable standards to be adopted in the typical road design are depicted in Figures E-T1 to E-T4. The geometry shown is set taking in
Geometric Design Manual-2002
Appendix F Procedure for Design
F.
PROCEDURE FOR DESIGN
F.1 Introduction This chapter has been prepared as a guide and checklist for personnel engaged in road design. It is not intended as a textbook nor should the contents be
Geometric Design Manual-2002
Appendix G Plans & Drafting
G
G.1
PLANS AND DRAFTING
General
The final plans are the graphic portrayal of the complete highway design. These plans, together with the specifications, enable the Engineer and the contractor to lo
Geometric Design Manual-2002
Appendix H Terms/Definitions
H.
TERMS AND DEFINITIONS
Figure H-1 Cross section Elements
A
Access Way whereby the owner or occupier of any land has access to a public road, whether directly or across land lying between his sand
Geometric Design Manual-2002
Chapter 12 AtGrade Junctions
12
AT-GRADE JUNCTIONS
12.1 Introduction A junction, or intersection, is the general area where two or more roads join. A disproportionate amount of traffic accidents occur at junctions, and thus fr
Geometric Design Manual-2002
Chapter 11 Mass Haul Diagram
11
EARTHWORK QUANTITIES AND MASS HAUL DIAGRAM
11.1 Introduction The topic of geometric design would be incomplete without a chapter devoted to the issue of earthwork quantities and a mass haul diag
Geometric Design Manual-2002
Chapter 10 Phasing of Horizontal & Vertical Alignment
10
PHASING OF HORIZONTAL AND VERTICAL ALIGNMENT
10.1 Alignment Defects Due to Mis-phasing Phasing of the vertical and horizontal curves of a road implies their coordination
Geometric Design Manual-2002
Chapter 2 Summary of Standards
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Geometric design the process whereby the layout of the road through the terrain is designed to meet the needs of the road users. Th
Geometric Design Manual - 2002
Preface
PREFACE
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
Geometric Design Manual-2002
Chapter 3 Route Corridor Selection
3 ROUTE CORRIDOR SELECTION
3.1 Project Cycle
Projects are planned and carried out using a sequence of activities known as the "project cycle." The cycle is composed of the following steps: id
Geometric Design Manual-2002
Chapter 4 Survey Requirements
4 SURVEY REQUIREMENTS
4.1 Introduction
This chapter presents the survey requirements associated with the geometric design process. Survey data for design purposes consists of mapping of sufficient
Geometric Design Manual-2002
Chapter 5 Design Controls & Criteria
5
5.1
DESIGN CONTROLS AND CRITERIA
Introduction
The choice of design controls and criteria is influenced by the following factors: the functional classification of the road; the nature of t
Geometric Design Manual-2002
Chapter 6 Cross Section Elements
6 CROSS SECTION ELEMENTS
6.1 Introduction
A cross-section will normally consist of the carriageway, shoulders or curbs, drainage features, and earthwork profiles. These terms are defined in the
Geometric Design Manual-2002
Chapter 7 Sight Distances
7 SIGHT DISTANCES
7.1 General Considerations
Simply put, sight distance is the distance visible to the driver of a passenger car. For highway safety, the designer must provide sight distances of suffi
Geometric Design Manual-2002
Chapter 8 Horizontal Alignment
8
8.1
HORIZONTAL ALIGNMENT
General
The design elements of the horizontal alignment are the tangent, or straight section, the circular curve, the transition curve (spiral) and the superelevation s
Geometric Design Manual-2002
Chapter 9 Vertical Alignment
9
9.1
VERTICAL ALIGNMENT
Introduction
The two major aspects of vertical alignment are vertical curvature, which is governed by sight distance criteria, and gradient, which is related to vehicle per
Geometric Design Manual-2002
Appendix I Abbreviations
I.
ABBREVIATIONS A
AADT AASHTO AAWSA ADT Average Annual Daily Traffic American Association of State Highway and Transportation Officials Addis Ababa Water and Sewerage Authority Average Daily Traffic
B