Characteristic on

road, such as grading, bridges and drainage structures. The surfacing of the road, whether of gravel, macadam or concrete or any of the other standard types, should be paid for from current receipts.

An added advantage of this method of financing is that pavements may be built to meet changing traffic conditions of the future. In the meantime the graded portion of the road is serving the needs of the community and at the same time is becoming thoroughly compacted, weak spots are developed and corrected and in general the road-bed is becoming more perfect year by year for the application of any subsequently chosen type of surfacing. Michigan is at the present time experimenting with these gravel roads as a foundation for a bituminous surface. It is believed that after several years of such maintenance an excellent foundation has been obtained.

Many miles of concrete road in California have been built and proposed in districts where materials must be transported at a great expense. Some of these roads have been cut through mountains of natural road surfacing material. Traffic on these roads in some cases is light. If this local material is used for surfacing in place of concrete the annual fixed charges and upkeep expense would be materially reduced, and at the same time an excellent road provided to meet traffic demands.

A continuation of the policy of building so large a mileage of frail hard surfaced roads, the life of which is short, from the proceeds of the sale of long term bonds, will ultimately embarrass the State or break down its good road program. California demands better roads, of longer life, properly financed. The economic development of the state depends on its good roads.

One-half of the net revenues derived from the Motor Vehicle tax were primarily and fundamentally assigned to the California Highway Commission for the purpose of maintaining roads that already had been constructed. From the figures that have been presented, it is plain that all this fund will be urgently needed for this purpose. It should be jealously guarded and applied to this maintenance and reconstruction work alone and not be diverted. to construction of new roads or to the carrying of general overhead charges.

(Signed) GEORGE JONES,
Road Commissioner Los Angeles Co.,

Chairman.
E. E. EAST, Road Engineer.
S. H. FINLEY, Supervisor Orange County.

Table No. 19

TABLE SHOWING LIFE, CONDITION AND COMPUTED TOTAL LIFE OF STATE HIGHWAYS IN SOUTHERN CALIFORNIA AS OF 1920

Weighted Computed Life.

609.36

14.69 yrs.

310.26

116.08

183.02

50.2%

19.3% 30.5%

MAINTENANCE COSTS AND REVENUES

The California Highway Commission has adopted a standard thickness of pavement and has built this practically on all types of soils and under all conditions of traffic. This, in the light of the present inspection, is a mistaken policy. Both the subgrade and the road must be adjusted to meet the condition of both soil and traffic. Soil surveys apparently are an essential feature of road location work and the Division Engineer should be given latitude to vary the type of construction to meet the local conditions which he is in a position to appreciate and which it is difficult to have given proper weight in a highly centralized office.

The report of the Committee on Subgrade and of the Committee on Slab enter into the discussion of the proper method of procedure under these varying conditions. It is recognized by both these committees that economies could be practiced where roads are built on sand and gravel soils, particularly under light traffic, that would be highly improper to practice where the pavement is laid on clay and adobe soils under heavy traffic.

The report of the Committee on Maintenance shows how serious the annual charges are for even the best types of roads under the best conditions.

The fixed charges on that portion of the thirty-three million dollar bond issue, out of which the 626 miles of road under consideration were constructed in Southern California, amounts to $738.00 per mile. The average cost of maintenance, widening and reconstructing the 602 miles of road built by the State in Southern California to date has been $615.00 per mile per year. It has not been feasible to determine the variation between the maintenance cost of roads built on different classes of soil, but it is apparent that the expense has been much greater where the pavement is built on the soils of a clay type.

Of a total of 96.75 miles of oil macadam pavement built by Los Angeles County, the average annual upkeep charge, including general maintenance, reconstruction, resurfacing and widening, has been $883.00 per mile. Some of these roads carry as high as six thousand tons of traffic in 24 hours. They were built on an average 6 inches thick and 20 feet wide under varying conditions of soil. These roads have been constructed and have been in service for an average of 7.88 years, the weight being given to their relative mileage. They were all classified as good at the date of their inspection, July, 1920.

The macadam roads of Los Angeles County under heavy traffic are maintained so that they are generally in good condition. This is accomplished by a continued process of patching with an asphaltic concrete surfacing material or an oil macadam, and the result seems to be a building up of the general character of the road rather than the reducing to an ultimate failure. After a road-bed of this kind has been constructed and in service through a term of years, it offers a foundation upon which either a concrete slab or any type pavement could be laid successfully. This has been done with good success by the County of Los Angeles on the Long Beach Boulevard.

The California Motor Vehicle Act provides license fees for all types of motor vehicles. The revenue derived from this tax was $5,250,000.00 for the fiscal year 1919-1920. According to the existing law, this fund is divided between the counties and the State equally, the result being an annual net revenue from this source to the State of about two and one-half million dollars. The State has constructed to date about 1,332 miles of paved roads. In addition there are 756 miles of unpaved mountain State roads which have to be maintained from this fund as well as 166 miles of paved roads transferred to the State by the counties, a total of 2,255 miles. In addition there are some graded but unpaved roads. On the assumption that two million dollars is distributed over the 2,500 miles of roads now built, the sum available for maintenance would be $800.00 per mile per year. The interest on the highway bonds is derived from the general fund. This revenue derived from the motor vehicle tax should be religiously guarded because of the immense amount of work which will be necessary to maintain our roads under the ever increasing load of traffic. A wise administration of this fund is imperative.

INSPECTION OF ROADS

The most accurate, as well as the most readily understood, test of the pavements that have been constructed in California on various soils and under existing traffic conditions, is the inspection of the pavements themselves as built by the State, by the various county engineers and by corporations. A field study, coupled with the historical data relative to each section, throws light on successful as well as unsuccessful types.

The time that has been allotted for this report is not sufficient to permit of extensive laboratory tests. Especial effort, therefore, has been made to study field conditions. This subject has been approached in the following manner:

A. Filling out, in the field, a standard blank form showing the conditions of sub-base and pavement, for each section or portion thereof.

B. The collection of historical data from the records of the State Highway Commission on standard forms used by the State showing the type and size of pavement, date constructed, the engineer and contractor in charge of the construction, character of sub-base, causes of failure, if any, etc. This historical data has been courteously furnished to the Automobile Club of Southern California by the State Highway Commission without charge for the clerical work.

C. A general description, accompanied by numerous photographs of each section, bringing out the special points of interest that have been noted.

This extensive data that has been so collected is not included in this report as such, but it has been used in the study which has been made and is compiled in the accompanying tables. It is the basis for the general statements contained herein.

In making these investigations the agreement was reached between the Automobile Club of Southern California and the State Automobile Association that the inspection of highways of the State will be divided between the two clubs on the southern line of Fresno County in the San Joaquin Valley and the southern line of Monterey County on the coast. While the inspections of these respective districts are thus assigned it was agreed that there should be an interchange of data between the engineers of the two clubs and mutual co-operation along the lines of consultation.

While the only road system described in detail in this report is the State highway, many miles of county roads have also been visited. Because of the numerous independent authorities in charge of the county roads, they furnish a greater variety of types for study.

As a result of the field inspection, the State highways have been segregated into three classes called "good," "fair" and "poor" roads in order to assist in arriving at general conclusions as to their condition, and so as to be able to express in terms that are readily understood, their present status. In order to make such classification, it is necessary to have ideas as clear cut as possible of what is intended; and particularly when these inspections are made by different persons, the classifications of the roads must be standardized; therefore, the following definitions have been adopted:

DEFINITIONS OF CONCRETE PAVEMENT
Classed as They Now Exist

1.

A Good pavement may have:

A. Transverse cracks every 15 to 30 feet, but without raveling.

B. Longitudinal side or diagonal cracks which show no raveling or movement of the slab at intervals of not less than 300 feet.

C. The sides of the concrete slab should be firmly resting on the sub-base.

D. The surface should be smooth so that machines without shock absorbers may run smoothly over its surface at all speeds up to 35 miles per hour.

E. Fine surface cracks or a few small irregular cracks are permissible for this classification if the concrete is otherwise good. Small triangular patches at the edges of the slab at the transverse cracks are permissible if not occurring at intervals of less than 200 feet.