19xx In July, People's Publishing House published Zhang's Traffic Economic Analysis of China, which mainly published the results of the author's econometric analysis of China's national economy and traffic statistics from 19xx to xx.

This book has a lot of calculation and analysis work, including the relationship between the total amount, turnover, average distance of passengers and cargo and the turnover of passengers and cargo with time, the average annual growth rate and increase rate of passenger and cargo turnover of various modes of transportation, and the growth relationship between cargo turnover and total industrial output value, total agricultural output value, total social output value and national income. The relationship between freight volume of provinces and municipalities directly under the central government and its industrial output value, per capita output value and time growth, the relationship between passenger turnover and industrial and agricultural output value, social output value, national income and consumption, the sharing ratio of passenger and freight turnover of various modes of transportation, the relationship between railway passenger and freight turnover and freight rate, and the growth index of national income consumption and industrial output value. And the Logistic curve model of passenger and cargo turnover in China, a model with I2 equation and the analysis of I965. I984 Econometric Model of China Transportation System. Among the published works on China's transportation economy, this book mainly uses econometric methods to make a comprehensive investigation on China's transportation industry, which should be regarded as the first one. Although the analysis process of the book is rough and the analysis conclusions in some places are not rigorous enough, we think it is still a useful attempt and exploration in the field of transportation economy.

In terms of the relationship between transportation and economy, the book talks about the long-term trend of passenger and cargo transportation in several places, which we think is correct. For example, the book says, "The experience of economic development shows that when the economic level is low, the traffic passenger volume increases slowly, but with the continuous development of the economy and the improvement of living standards, the traffic passenger volume will also increase"; It is also said that "in the early stage of economic development, the freight volume increased sharply", while "with the continuous improvement of the level of economic development, the growth rate of freight volume slowed down relatively" (see pages 47 and 2 10- in this book). We believe that these points are basically in line with the general changes in passenger and cargo transportation in industrial countries since the beginning of the industrial revolution. If the book can fully demonstrate these conclusions, and more specifically analyze at what level of economic development, or at what stage, passenger traffic will increase rapidly, while the growth rate of freight volume will decrease, and on this basis, make predictions on the future transportation development of China, then we believe these conclusions will be more convincing. However, the author's argument is not enough. We think that his analysis is somewhat divorced from the conclusion, and he failed to make good use of his analytical tools.

First of all, the author only pays attention to the quantitative characteristics of transportation products in terms of weight and distance, but does not pay more attention to the differences in the displacement direction, speed, comfort, convenience and physical characteristics of goods (such as solid, liquid and volume). ) and packaging saving. Due to natural geography and resources, different countries and regions have different demands for passenger and cargo transportation in different social and economic development periods, and the development of transportation industry is not only based on people kilometers. Generally, the difference of transportation demand and transportation products between people kilometers and tons kilometers is more obvious in the higher stage of economic development, and the demand for transportation capacity is more manifested in these aspects. If we can't pay enough attention to these changes in the study of transportation economy, it is easy to make quantitative analysis simple and superficial. Secondly, in the regression analysis of freight volume, the selection of relevant variables ignores the industrial sectors that have a decisive influence on some transportation. For example, according to the materials cited in the book, coal has always occupied the first place in railway freight volume, and its proportion has increased from 30 in the early 1950s to nearly 40% in the 1980s, while the railway freight volume caused by smelting substances including steel has reached more than 6 times of its own output (page 62-65, 130- 1s 1). The calculation and analysis of railway traffic volume in this book does not seem to introduce coal output and steel output into the correlation regression equation, which obviously reduces the persuasiveness of this analysis. In fact, according to the professor's calculation, the output of coal and steel is closely related to the railway traffic volume. The correlation coefficients of coal output and railway traffic volume, steel output and railway traffic volume, and the * * * homocorrelation coefficients of these two factors and railway traffic volume are all around 0.99, which exceeds the equation used by Zhang. Under the condition that the ratio of coal freight volume to steel output is linear and stable, it is obviously unreasonable to analyze and study the freight volume without considering their influence.

Thirdly, the book's analysis of China's transportation elasticity, especially freight elasticity, obviously contradicts the forecast of future transportation demand. Page 1 19 in the book says: the average elasticity of total F transportation volume to total industrial output value is 19xx- 19x'x years, 1.3 12 years,19xx-. Considering the lack of transportation capacity during this period, the actual freight volume of latent flowers should be slightly higher than the statistical freight volume. "It can be considered that the actual elasticity of freight volume in China has reached about 0.7.

That is, the ideal value of relative balance between production and freight. "I also think that this decline shows that China's economic structure and industrial structure are becoming more and more mature and reasonable. Page 2 15 also calculates that the turnover of goods and the short-term elasticity of the national economy in China are 0.6? 42。 However, the book predicts instead: "At present, China is entering a new era of economic development, and the traffic demand is bound to increase rapidly. In the next 10 years or so, the growth rate of transportation will be extremely fast, and the average annual growth rate of freight will be close to that of the national economy. "After 20 years, the growth rate of freight will slow down, which is lower than the growth rate of the national economy. It is difficult to understand the ideal of 0.65 between freight and industrial output value and national economy. Why does the elasticity value of 0.7 suddenly rise to around 1, that is, "the average annual growth rate of freight volume is close to the growth rate of national economy". For a book with measurement as the main tool, we have reason to ask for an explanation of the relationship between the two and the reason for the sudden sharp increase in freight. In addition, the analysis of various transportation elasticity in this book is always calculated according to logarithmic regression equation, so as to get the constant elasticity value. We know that according to the calculation method of elastic value in economic analysis, only exponential model can calculate constant elastic value through logarithmic equation, and other models, including linear model, are not so simple. The regression equations established in "China Transportation Economic Analysis" are mostly linear in one variable or multiple variables, but the author did not give the necessary explanation or explanation when simplifying the calculation of elastic values with logarithmic equations, which made people doubt the accuracy of these elastic values. Simplified calculation is allowed, but the conditions for simplified calculation of the original model should be explained.

Fourthly, in the tenth and eleventh chapters of the book, an econometric model of China's transportation system is established, which contains 12 equations. The quality of the model lies not only in the number of equations, but also in the best use of fewer equations, but also in the requirement that these equations have strong universality and can accurately describe the movement of the actual economic system. The establishment of Zhang's mode is a beneficial attempt, but his mode has quite serious defects. Only the following points are pointed out here: (1) In addition to the output of coal and steel, several most important gross indicators in China's economic statistics, such as the total industrial and agricultural output value and the total social output value, have not been included in the model, and the author has repeatedly analyzed their close relationship with the transportation volume in the book; (2) The total freight volume in the book is the sum of freight turnover of railways, highways, waterways and aviation, but excluding pipelines. Pipeline is an important mode of energy transportation. In I9xx, the turnover of pipeline transportation in China has exceeded 6 billion tons kilometers, which is 1.7 times that of highway transportation in that year. It is incomplete to ignore this important mode of transportation. (3) The existing 12 equation itself needs careful scrutiny? For example, the equation 1 (railway freight turnover =1147.15+1256 gross industrial output value -6 1). C4 17 empty cargo turnover), one * * two. Why do you want to put the variables with the least influence in the equation?

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