American Rural Highways   By: T. R. (Thomas Radford) Agg (1878-1947)

Also, on pages 47 48, the Greek letter theta is represented by THETA. In chemical and mathematical notations, a subscript is enclosed in braces and preceded by an underscore (e.g., H {2}O.)]

AGRICULTURAL ENGINEERING SERIES

E. B. MCCORMICK, CONSULTING EDITOR

FORMERLY DEAN OF ENGINEERING DIVISION KANSAS STATE AGRICULTURAL COLLEGE

AMERICAN

RURAL HIGHWAYS

McGraw Hill Book Co. Inc.

PUBLISHERS OF BOOKS FOR

Coal Age Electric Railway Journal Electrical World Engineering News Record American Machinist Ingenieria Internacional Engineering & Mining Journal Power Chemical & Metallurgical Engineering Electrical Merchandising

[Illustration: Frontispiece ]

AMERICAN RURAL HIGHWAYS

BY

T. R. AGG, C.E.

PROFESSOR OF HIGHWAY ENGINEERING IOWA STATE COLLEGE

FIRST EDITION

MCGRAW HILL BOOK COMPANY, INC. NEW YORK: 239 WEST 39TH STREET LONDON: 6 & 8 BOUVERIE ST., E. C. 4 1920

COPYRIGHT, 1920, BY THE McGRAW HILL BOOK COMPANY, INC.

PREFACE

AMERICAN RURAL HIGHWAYS was written for use as a text or reference in courses dealing with rural highways and intended for agricultural engineers, students in agriculture and for short courses and extension courses. The reader is assumed to have familiarity with drawing and surveying, but the text is adapted primarily for students who do not receive training along the lines of the usual course in Highway or Civil Engineering.

The text is intended to familiarize the student with the relation of highway improvement to national progress, to indicate the various problems of highway administration and to set forth the usual methods of design and construction for rural highways in sufficient detail to establish a clear understanding of the distinguishing characteristics and relative serviceability of each of the common types of roadway surface.

Experience with classes made up of students in agriculture or agricultural engineering and with trade school students in road making served as a guide in the selection and arrangement of the material. Detailed discussion of tests of materials and of the theory of design has to a considerable extent been eliminated as being outside of the scope of the course for which the text is intended.

In the preparation of American Rural Highways reference was had to many books on highway subjects and to current periodical literature. Wherever direct extracts were made from such source, appropriate acknowledgment appears in the text.

T. R. AGG

AMES, IOWA, AUGUST 18, 1920.

CONTENTS

PREFACE vii

CHAPTER I

THE PURPOSE AND UTILITY OF HIGHWAYS

Transportation Problem National in Scope Development in Traffic Location or Farm to Market Traffic Farm to Farm Traffic Inter City Traffic Inter County and Inter State Traffic Rural Education Rural Social Life Good Roads and Commerce 1 12

CHAPTER II

HIGHWAY ADMINISTRATION

Township Administration County Administration State Administration Federal Administration Special Assessments Zone Method of Assessing General Taxation Vehicle Taxes Sinking Fund Bonds Annuity Bonds Serial Bonds Comparison of Methods of Issuing Bonds Desirability of Road Bonds 13 28

CHAPTER III

DRAINAGE OF ROADS