The State of California has now voted $73,000,000 for the building of good roads and the counties $42,000,000 more, a total of $115,000,000. Over half of this immense sum has been expended. The inspection that has been made of the State roads in Southern California shows that today thirty per cent of the pavements are in poor condition with an average age of pavement of 4.24 years. Probably ten million dollars' worth of State and county pavements in Southern California have failed. While it must be admitted that these pavements have been too narrow and too frail and often foundation conditions were defective, it is also certain that a large portion of these failures have been caused by excessive and illegal overloading of the slab. Table No. 17, page 62, reveals that 70% of the 1-ton trucks, weighed on the country roads, were loaded in excess of the legal limit, that 92% of the 5-ton trucks, 100% of the 52ton trucks and 100% of the 6-ton trucks carried illegal loads. The State law limits the load to 800 pounds per inch of width of tire in contact with the road. The 192 trucks weighed on the country roads show that the average overload on a 1-ton truck was 61 pounds per inch of tire while the average overload of the 12-ton trucks was 191 pounds, 2-ton trucks 163 pounds, 3-ton trucks 145 pounds, 5-ton trucks 274 pounds, 5-ton trucks 245 pounds and the 6-ton trucks 416 pounds. The maximum concentration of load per inch of tire on the road with these trucks ran as high as 1,560 pounds, with a maximum total load on one rear wheel of 17,916 pounds. As shown in Table No. 15, page 56, 500 trucks were weighed on the public scales in the City of Los Angeles and much the same results were obtained for the town trucks as were found for those in use out on the country highways. The table shows that 75% of the 1-ton trucks were overloaded, 60% of the 2-ton trucks, 75% of the 3-ton trucks, 84% of the 4-ton trucks and 67% of the 5-ton trucks. Based on comparison with the loads allowed by law, the average overloads per one inch width of rear tire of the trucks weighed in town as compared with the State's 800-pound limitation were as follows: 1-ton trucks 259 pounds; 2-ton trucks 257 pounds; 3-ton trucks 109 pounds; 3-ton trucks 345 pounds; 4-ton trucks 313 pounds; 5-ton trucks 292 pounds. The maximum overloading per one-inch width of tire as compared with the State law was as follows: For 1-ton truck 738 pounds; 2-ton trucks 812 pounds; 2-ton trucks 720 pounds; 3%-ton trucks 768 pounds; 4-ton trucks 877 pounds and 5-ton trucks 1,040 pounds. The maximum concentration of load on one rear wheel for the larger of these town trucks was as follows: 3-ton trucks 8,925 pounds; 32-ton trucks 10,960 pounds; 4-ton trucks 10,075 pounds; 5-ton trucks 11,280 pounds. The loads of about 60% of these town trucks originated on or were destined for the State or County highways. It seems incredible that in the face of such a record of destruction of the State pavements that these persistent, unreasonable and illegal loads should continuously be permitted to traverse our highways. There has been practically no serious attempt made on the part of either State or County authorities to enforce the laws that have been provided by our Legislature for the protection of these roads. A very few and far scattered arrests have been made, but as far as known but one case has been carried as far as the County Superior Court of the State and in this instance a decision was rendered in favor of the prosecution, in Alameda County. The law to the layman seems perfectly clear and capable of enforcement. The truck dealers and manufacturers, as a rule, are opposed to the overloading of these trucks and advise against it. There are, however, some notable exceptions where truck advertisements have been issued by dealers which would justify prosecution. There is a pronounced tendency to increase the size and capacity of trucks because the cost per ton mile of hauling large loads is less than for small. The 72-ton truck has made its appearance on our highways. The field inspections clearly show that our roads already are breaking down under excessive weights and any increase in such loads should be strongly resisted by all those who are interested in the preservation of our highways. It really is to the interest of both the truck dealer and the operator to keep these loads within reasonable limitations, otherwise they will bring down upon themselves restrictions under the law which are apt to be unreasonable, to say nothing of the breaking down of the highway which is essential to their existence. The careful study of the Committee on Slab Construction, which is attached to this report, finds that the maximum load on any wheel, within reasonable limits of the width of tire, is a controlling factor in determining the necessary thickness of the slab or in breaking down existing slabs. No load in excess of 10,000 pounds should be allowed on any one wheel. The effect of pneumatic tires on the pavement has been demonstrated to be less injurious when heavily loaded than in the case of solid tires. It follows that the use of the pneumatic tires should be encouraged by the law both in increasing the speed limit for loaded trucks having pneumatic tires and possibly by reducing the license fee on trucks using such tires. Such a provision has been recommended in the Uniform Motor Vehicle Law which is referred to in the report of the Committee on Trucks and Truck Laws. The hauling of freight in trucks on improved highways is a new economic development of great value to the community at large as well as to the truck owners. It has greatly enhanced the efficiency both of farmers, manufacturers and merchants in the distribution of their products. This business should be fostered and encouraged. Any attempt to radically reduce the legal loads or speeds probably would result in defeat. These trucks are intercounty and to a limited extent inter-state in their operation. Their load should not be regulated by a great variety of differing county or state laws. The situation is being met by those interested in the trucking business by the presentation of a National Uniform Motor Vehicle Law to apply throughout the United States. This law is closely in harmony with the existing California laws. There appears no reason why the portions of this law relative to weights should not be adopted by California with a single limitation that not over 10,000 pounds should be allowed on any one wheel on the California highways because they are not built so as to hold up under any greater loads. See Committee Report on Laws. The State and County authorities allege that it is difficult for them to enforce the existing law because arrested parties are brought before Justice Courts where local influences interfere with convictions. In at least one case successful appeals have been made to the County Superior Court. It is outside of the scope of an engineering report to discuss legal procedure, but it is suggested that if possible there should be some State authority devoid of local influence made available for the prosecution of those who flagrantly violate these traffic laws thus causing enormous financial loss to the people of California as well as interfering with the legitimate use of the highway. It cannot be too strongly stated that unless some enforcement of reasonable laws with reference to the use of the public highways can be accomplished that our bridges and pavements will continue to be destroyed at an alarming rate. Our inspectors find that the presumptive life of our California pavements under present traffic will not be over 15 years. Growth in Numbers of Automobiles and Trucks in California Rapid growth in the utilization of motor vehicles has developed in the last decade. Following the building of hard surfaced roads by the State and counties, the growth in number of vehicles was tremendous. Diagram No. 6, page 65, shows in 1913 a total of 103,698 motor vehicles were registered and on July 1, 1920, 481,350 autos and trucks were licensed-a growth of 464% in 8 years. Out of 58 counties in the State, the 14 counties in the territory of the Automobile Club of Southern California in 1913 had 63% of the auto and truck registration and in 1920 these same counties had 50% thereof. REPORT OF THE COMMITTEE ON MAINTENANCE Mr. George Jones, Chairman, Road Commissioner, Los Angeles County. Mr. S. H. Finley, Supervisor, Orange County. MAINTENANCE Time is the most essential factor in determining the relative values of various types of pavements. The first cost is not the only one attached thereto, much propaganda circulated prior to bond elections to the contrary notwithstanding. There is no such thing as a permanent pavement. Complete and reliable data as to the cost of maintaining highways in the United States is rare. This can largely be explained in that Highway Engineers have been busy developing types and in raising money for construction and there has been little time devoted to investigating the cost of upkeep. The life of our present day highways has been too short to permit little more than a rough indication of what the total upkeep is. This study may be divided into two parts. First, an investigation dealing with the actual total upkeep to date, and second, the estimated total cost over a period of years. The major portion of the report deals with the State Highways of Southern California. Los Angeles County oiled macadam and concrete, and Orange County concrete roads have been investigated and data compiled as to their first cost and upkeep. The terms used in the discussion are here defined as follows: General Maintenance: Minor repairs to pavement and oil surface, repairs to guard rail, mowing weeds, grading in shoulders, drainage, etc. Upkeep: Includes reconstruction, resurfacing, additions, and general maintenance. Fixed Charges: Interest and bond retirement fund applied to original cost of road. Average Weighted Age: This is the quotient of the sum of the miles, times their respective age, divided by the total miles. Overhead: Includes both Headquarters, Division administration and supervision, undistributed charges, compensation insurance, repairs to equipment, etc. This amounts to approximately 20%. A knowledge of the life of a pavement is essential to the determination of its economic value. The inspection of 602 miles of State Highway, with an average weighted age of 4.24 years, disclosed that 50.2% were good, 19.3% fair and 30.5% poor. Some 32 miles of this pavement have been resurfaced with either concrete or a heavy bituminous carpet at a cost in excess of that of the original pavement. The average weighted age of this resurfaced pavement is 4.3 years. Tabulating the roads according to years built and noting the per cent of failure to July, 1920, an indicated life of roads built during each of the years 1913 to 1919 was obtained. From this an average weighted life of 14.69 years was found for the 602 miles. Table No. 19, page 79. Frederick Stuart Greene, Commissioner of New York State Highways, writing in Engineering News Record of August 21, 1919, in discussing the relative merits of concrete and macadam pavements finds that "it is conservative to suppose that the concrete pavements as now laid will last 15 years" and also that the average life of a macadam pavement to the point at which re |