Chapter II: 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

The Necessity for Drainage--Importance of Design--Surface Drainage--Run-off--Ordinary Design of Ditches--Underground Water--Tile Drains--Lying Tile--Culverts--Length of Culvert-- Farm Entrance Culverts--Metal Pipe--Clay and Cement Concrete Pipe--Concrete Pipe--Endwalls for Culverts--Reinforced Concrete Box Culverts--Drop Inlet Culverts 29-41

CHAPTER IV

ROAD DESIGN

Necessity for Planning--Road Plans--Problems of Design-- Preliminary Investigations--Road Surveys--Alignment-- Intersections--Superelevation--Tractive Resistance--Rolling Resistance--Internal Resistance--Air Resistance--Effect of Trades--Energy Loss on Account of Grades--Undulating Roads-- Guard Railing--Width of Roadway--Cross Section--Control of Erosion--Private Entrances--Æsthetics 42-62

CHAPTER V

EARTH ROADS

Variations in Soils--Variation in Rainfall--Cross Sections Elevating Grader--Maney Grader--Slip Scraper--Fresno Scraper--Elevating Grader Work--Use of Blade Grader-- Costs--Maintenance--Value of Earth Roads 63-73

CHAPTER VI

SAND-CLAY AND GRAVEL ROADS

The Binder--Top-soil or Natural Mixtures--Sand-clay on Sandy Roads--Sand-clay on Clay or Loam--Characteristics--Natural Gravel--The Ideal Road Gravel--Permissible Size of Pebbles-- Wearing Properties--Utilizing Natural Gravels--Thickness of Layer--Preparation of the Road--Trench Method--Surface Method--Maintenance 74-88

CHAPTER VII

BROKEN STONE ROAD SURFACES

Design--Properties of the Stone--Kinds of Rocks used for Macadam--Sizes of Stone--Earth Work--Foundation for the Macadam--Telford Foundation--Placing the Broken Stone-- Rolling--Spreading Screenings--Bituminous Surfaces--Maintenance Characteristics 89-97

CHAPTER VIII

CEMENT CONCRETE ROADS

Destructive Agencies--Design--Concrete Materials--Fine Aggregate--Proportions--Measuring Materials--Preparation of the Earth Foundation--Placing Concrete for Two-course Road--Curing the Concrete--Expansion Joints--Reinforcing--Bituminous Coatings on Concrete Surfaces--Characteristics--Maintenance 98-105

CHAPTER IX

VITRIFIED BRICK ROADS

Vitrified Brick--Paving Brick--Repressed Brick--Vitrified Fiber Brick--Wire-cut-lug Brick--Tests for Quality--Other Tests-- Foundation--Sand Bedding Course--Sand Mortar Bedding Course-- Green Concrete Bedding Course--Bituminous Fillers--Mastic Fillers--Marginal Curb 106-115

CHAPTER X

BITUMINOUS ROAD MATERIALS AND THEIR USE

Classes of Bituminous Materials--Coal Tar--Water Gas Tar--Natural Asphalt--Petroleum Asphalt--Mixtures--Classification According to Consistency--Road Oils--Liquid Asphalts--Asphalt Cements-- Fillers--Bitumen--Specifications--Surface Treatments--Applying the Bituminous Binder--Finishing the Surface--Patching-- Penetration Macadam--Foundation--Upper or Wearing Course-- Patching Characteristics--Hot Mixed Macadam--Foundation--Sizes of Stone--Mixing the Wearing Stone--Placing and Wearing Surface--Seal Coat--Characteristics--Asphaltic Concrete-- Bitulithic or Warrenite--Topeka Asphaltic Concrete--Foundation --Placing the Surface--Characteristics 116-129

CHAPTER XI

MAINTENANCE OF HIGHWAYS

Petrol Maintenance--Gang Maintenance--Maintenance of Earth, Sand-clay, Gravel and Macadam Roads 130-134

Index 135

AMERICAN RURAL HIGHWAYS