EXCEPTION SHEETS Practically all carriers, either individually or thru rate associations, issue exception sheets to the classifications proper. These exceptions in many cases authorize the application of other ratings and prescribe different methods of preparation for shipment. It follows, therefore, that the exception sheets should be referred to in determining the classification applicable to the offerings between points, or to or from points, to which the exception sheet applies. The existence of a favorable exception enables the industry to select jobbing centers and to distribute either thru them or thru warehousemen. GENERAL RULES The rules incorporated in the tariff proper and the rules appearing in the classification must be analyzed to determine their effect on the traffic of the industry. A concern specializing in the handling of articles of unusual length that require two or more cars for their transportation will find the extra length rules of the classification and of special tariffs of particular interest. The concern shipping packages of small weight is particularly interested in the minimum charge rules which appear in the classifications and in many of the individual tariffs. The minimum charge is a vital factor in determining whether it is more advantageous to ship by express than by freight. SUPPLEMENTAL EVIDENCE Among others, the following important questions have been considered by public commissions charged with the duty of regulating the transportation cnarges of common carriers: the advantage of locations possessed by an industry or a community; additional service in the form of equipment; transit privileges and terminal service; back hauls or out-of-line movements; car-mile or train-mile revenue; various elements of competition, such as cost of service, length of haul, and equipment furnished; rates in the opposite direction; rates on manufactured versus crude articles; origin of traffic; previous rates; density of population; public interest; rates via competing carriers; risks by loss or damage; two or three line haul; value of commodity; value of service; volume or bulk of traffic; and weight or bulk of shipment. Many of these topics are touched upon in a treatise on Grounds of Proof in Rate Cases and Procedure before the Interstate Commerce Commission, prepared by the LaSalle Extension University, Chicago, Illinois. The senior rate clerk of the department can be intrusted with the preparation of the detail following tariff and rate studies, and should bring the discrepancies to the attention of the traffic manager. It may then be determined whether the issue is of sufficient importance to the firm to warrant the institution of a formal complaint before a public utility commission, and if so, what factors are to be relied upon to sustain the contention of the industry that the change in rating advocated has merit. CHAPTER XIV TRAFFIC GRAPHS, CHARTS, AND MAPS Purpose and Value of Graphs-Two-Dimension Graphs: sion. PURPOSE AND VALUE OF GRAPHS It is the purpose of this chapter to make clear the utility of graphs, and to illustrate the types and the method of construction by a number that have been used in industrial traffic work and in rate cases before the public utility commission. In the preparation of rate exhibits and in the analysis of statistics of traffic work and transportation charges, graphs are well-nigh indispensable. Graphs have been aptly styled "pictures of figures or conditions." Their preparation entails little difficulty or expense, and they enliven formidable arrays of figures. In this connection an authority has said that long rows of figures must be thoroly studied in order to convert them mentally into quantities which may be compared as to size. This is a tedious task which many executives have learned to dread. The reason is a simple one-a row of figures does not tell a story of itself. A somewhat involved mental process is required to grasp and to visualize the real facts. TWO-DIMENSION GRAPHS Since the problems of the traffic department usually involve two factors, such as earnings and time, or distance and elevation, or population and tonnage, graphs may ordinarily be constructed most clearly in two dimensions, vertical and horizontal. In preparing graphs of this type, it is necessary to use cross-ruled paper (quadrille ruled); if this cannot be secured from the local stationer, ordinary paper may be so ruled. Graphs of this type are frequently employed in showing the trend of class rates and the relationship of one class rate to another. They are remarkably advantageous in arguments for rate readjustments. In Fig. 42 the first-class, fourth-class, and sixth-class rates have been charted in the manner contemplated. The numbers on the left-hand side of the graph show the rate in cents per 100 pounds, and the numbers at the bottom show the various distances for which rates are established. The scale of rates used in preparing this graph is as follows: |