| Road congestion and environmental pollution are growing problems around the world.Owing to its large capacity,high security,low cost,low unit carbon emission and other advantages,Rail-road Intermodal Transport(RRIT)has gained attention from all over the world.The development of railway container transportation in China is slow,far behind Euramerican developed countries,although it started very early.China's railway container freight volume account for only 5.4%of total railway freight,far below the developed country's percentage(30%to 40%).The proportion of rail transport is only about 2%in China's ports collection and distribution system.Therefore,making reasonable and effective development strategies to promote the rapid development of RRIT in China,is of great significance to reduce social logistics cost and optimize comprehensive transport system structure.On the basis of deep analysis of the existing researches,firstly,in order to analyze the impacts of different influencing factors to the competitiveness of RRIT,we use random utility theory to construct the competitiveness model of RRIT based on the generalized cost function.Secondly,we select the internalized carbon emission cost strategy as the research objective,which is closely related to the global hot issue"Greenhouse Effect",and use the competitiveness model to quantify the effectiveness of this strategy to RRIT's developments.Finally,we choose the subsidy policy as the research objective,which is effective to promote the development of intermodal transport in Europe,and build two bi-level programming models to research the mechanism of different subsidy policy to promote the RRIT's developments.The main contents and conclusions of the dissertation are shown as follows.(1)Based on the operation organization mode of block container trains on the three-level railway container transport network,we analyze the whole container transport procedures of truck-only transport and RRIT respectively.And we segment the whole process transportation time and cost according to each procedure.Thus,we construct truck-only transport's and RRIT's generalized cost function based on their whole process.The analysis results indicate that truck-only transport is a high-efficiency transport mode at the cost of high-cost.Under the different combination of freight distance and road drayage distance,the RRIT's transport cost accounts for 43.1%to 60%of its generalized cost,however,the proportion of truck-only transport cost in its generalized cost is bigger.(2)Based on the truck-only transport and RRIT's generalized cost function,we build the competitiveness model of RRIT according to random utility theory.And we use this model to analyze the impact of each influencing factor to RRIT's competitiveness,including truck-only transport basic rate,road drayage rate,railway rate,value of time,the speed of block train,the container fleet of block train,average arrived container fleet every day and round factor.Considering that these factors' dimensions and ranges are different,we use the elastic coefficient method to further analyze the effect of different factors.The results show that the impact of the same factor to RRIT's competitiveness is different while the combination of freight distance and road drayage distance is different.While RRIT's freight distance is small and road drayage distance is big,the absolute values of truck-only basic rate's,road drayage rate's and value of time's elastic coefficient is greater than 1.And the smaller the RRIT,s freight distance,the larger the absolute values.The factors(except for road drayage rate)belong to the RRIT system is inelastic,indicating that the effect of only improving a certain factor to promote RRIT's developments is poor.Therefore,in order to achieve good effect,we must optimize each RRIT's procedure from a systemic perspective.(3)Considering the various transporting and handling equipment involved in the RRIT's whole process,we build the carbon emission calculation model of the RRIT's whole process based on the semi-life cycle method,which can calculate the carbon emission of each RRIT's procedure.We convert the carbon emission calculated by this model into carbon emission cost according to Social Cost of Carbon(SCC,about 1500 RMB/tCO2e).And we analyze the impact of internalizing carbon emission cost to the RRIT's competitiveness,and quantify the effect of current carbon pricing level on promoting the RRIT's developments.The results indicate that under different combination of freight distance and road drayage distance,the increase of the RRIT's share is between 7.8%and 11%after internalizing carbon emission cost according to SCC.However,the world's carbon pricing level is much lower than the SCC,and the carbon pricing level(less than 40 RMB/tCO2e)in China is lower than the world average level,which leads to the effect of internalizing carbon emission cost strategy on enhancing the competitiveness of the RRIT in China is negligible.(4)Based on the policy of subsidizing the carrier and subsidizing the shipper,we build two bi-level programming models(SCM and SSM)which can reflect the interaction mechanism between the government department,the railway company and shippers.We design a Hybrid Genetic Algorithm(HGA)to solve these two models,which merges Genetic Algorithm(GA)and Method of Successive Averages(MSA).The results indicate that using discrete choice model(eg,Logit)to study the impact of subsidy policy on RRIT based on single OD may overestimate the effectiveness of subsidy policy.With the increase of the subsidies,the growth trend of RRIT's share is relatively flat in our SSM model,while the trend was growing exponentially in the existing research(eg,Logit Model).When the subsidies increase from 0 to 0.145 RMB/tkm,the RRIT's share increase by 30%and 71.6%in our SSM model and in the existing research respectively.There are two reasons why the existing researches overestimate the effectiveness of subsidy policy,on one hand,the RRIT's network is used to research the impact of subsidy policy in this dissertation which involves many pairs of OD demand.Due to different freight distance and road drayage distance in different OD,the impacts of subsidy policy on different OD's RRIT are different.Therefore,compared with the average effect of subsidy policy on many ODs' RRIT,the effect on single OD' RRIT be of one-sidedness.On the other hand,the result of subsidy policy promoting RRIT's developments is not a simple mode split,but the result of the interplay between the government department,the railway company and shippers.And the railway company's pricing strategy will suppress the promotive effect of subsidy policy in the interplay. |
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