1. Introductory Statement.. 2. INDEX PART I The Various Highway Acts and Funds and the State Highway System 2.1 The Highway Act of 1909. 2.2 The Highway Act of 1915. 2.3 The Highway Act of 1919. Table of Proposed Highways Act of 1909.. Map of Proposed Highways Act of 1909 showing completed work. Pages 9-10 11 11 12 12 13 14 14 15 16 17 18 19 20 Table VI, Interest, Depreciation, etc., on Items of Equipment. 30-32 PART II 4. Subgrades 4.1 Adobe and Clay Subgrades. 4.2 Drainage of Heavy Subsoils. 4.3 Uniform Policy Recommended for Settlement of Heavy Fills. Diagram 1.-Sketches of Adobe Action on Concrete Slabs 5. Thickness of Road Slabs 33 37 39 39 40 41 5.01 Pavement Failures from Inspection Reports. 42 5.02 Character of Subgrade under Poor Pavements. 42 42 5.04 Relation of the Age of Pavement to Areas of Failure. 43 43 Seattle Tests... 45 INDEX Continued Table VIII 5.06 Should a Concrete Slab be of Uniform Thickness or Variable Cross-section. 5.07 Importance of Longitudinal Cracks in Concrete. 5.08 Minimum Thickness of Plain Concrete Road Slabs for California Conditions 5.09 Thickness of Concrete Road Slabs by Ultimate Cost Analysis. Present Cost of Concrete Pavements Constructed in 1914.. Pages 47 48 48 51 54A 56 57 Total Maintenance by Years, of Pavements 58 Ultimate Cost of Pavements in Table VII 59 Plan Showing Tools used in Placing Expansion Joint-Washington. 63 64 65 5.13 Pavement Crowns. 66 Figure 2. Standard and Special Sections California State Highways 66A 67 6.2 Widths of Pavements in California Highway System and Comparison with Other States..... 6.3 Original State Highway Program of Shoulder Construction. 6.4 Relative Economy in Extra Width of Concrete Pavement by Comparison with Rock and Oil Shoulder Construction... Table XV-Shoulder Maintenance and Improvement Costs. 6.5 Shoulders and Berms. Bituminous and Asphalt Surfacing Cost Analysis of Thin Bituminous Carpets and Topeka Mixtures in California Table XVI-Ultimate Costs both Types of Surfacing. 70 72 74 75 222 22 77 77 77 78 78 79 80 81 Figure 3.-Maintenance Curves both Types of Surfacing. 7.4 Slipperiness Due to Asphaltic Wearing Surface.... 7.5 Necessity for Surfacing Concrete Roads to Prevent Wear. 7.6 Double-Decking and Surfacing Old Concrete Roads. 83 7.7 Black (Asphaltic Concrete) Base versus Cement Concrete Base. 84 Low Ultimate Strength of Concrete in California Roads. 8.3 Deterioration of Cement Due to Storage. 8.4 "Dry" Concrete versus Wet Mixtures. 8.5 Present State Highway Specifications. PART III 9. Traffic and the Motor Vehicle Act General Discussion of Traffic Problem. Taxation of Motor Vehicles. 10. Need for Increased Fund in California. Recommended Modification in Motor Vehicle Law. Table XVII-Motor Vehicle Tax in Various States. Figure 4. Curve of Motor Vehicle Registration. Figure 5.-Curves of Highway Maintenance and Reconstruction and Motor California Highway Commission Policies 10.4 Dangerous Grade Crossings and Suggestions for their Elimination. 106 111 10.9 Cost of Work Affected by Attitude Toward Contractors. 11.6 A Possible Program to Cover Expenditure of Remaining Highway Funds. Estimate of Costs.. 117 120 Figure 2-Curve Showing Total Expenditures from Maintenance Fund. 124 125 Curve of Total Highway Expenditures by Years. 126 I. INTRODUCTORY STATEMENT Following the employment of the authors "to make a comprehensive examination of the State highway system and a report covering all of the facts as found," a brief summary of the main subdivisions of the plan of investigation was submitted to the Chairman of your Good Roads Committee, Mr. H. J. Brunnier, and with his approval the actual work was then commenced. This preliminary summary included: 1. Inspection trips over most of the State. 2. Obligations under the various bond issues, and completed programs. 5. Technical studies of pavements and principal factors contributing to failures. 6. Laboratory tests that might prove of value. 9. Specific recommendations as determined by a study of the facts and data collected. With the completion of the investigation, the general summarization given above has been covered in considerable detail. Inspection trips covering approximately 4,000 miles of travel by automobile have been completed, and each section of State highway visited included a survey of: Through the courtesy of the Highway Commission, records showing the age, width and type of each section of paved highway were furnished on request prior to the various trips, and these aided considerably in the study of field conditions. From time to time additional data covering specific subjects such as lists of reinforced pavements, thickness and mixtures of concrete road slabs, laboratory tests of aggregate, etc., etc., together with plans, maps, forms and other general information, have been requested from the Commission and in every instance the material has been freely furnished. To check over highway expenditures and collect the mass of cost and maintenance data required, it was arranged for our own accountants to have access to the Highway Commission's books and records and a study of the data obtained forms an important part of this report. As a check to certain theoretical and mathematical deductions in this report, certain tests of concrete slabs and adobe soil were arranged for in consultation with and under the direction of Professor Charles Derleth, Jr., of the University of California, with Professor C. T. Wiskocil directly in charge of the testing operations. Traffic counts were made at several points to furnish data on specific sections of highway. A more comprehensive study was made by the Automobile Club of Southern California and a similar study was therefore considered a needless duplication in the north. Additional data was collected from such sources as the Railroad Commission, Motor Vehicle Department, Bureau of Public Roads at Washington, and a considerable volume of information. was obtained from correspondence with thirty-five other states |