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"World Transport Policy & Practice" Volume 10,Number 3 - Commentary

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  • EcoPlan, Paris
    Dear Daryl Oster and Sustran- and NewMobilityCafe-members The usefulness of scientific journals is sometimes discussed - someone told me that the average
    Message 1 of 1 , Jan 5, 2005
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      Dear Daryl Oster and Sustran- and NewMobilityCafe-members

       

      The usefulness of scientific journals is sometimes discussed – someone told me that the average readership of a paper in a scientific journal is less than two (plus the referees and the editor). So getting a comment for your paper published world-wide within 24 hours of publication is really something and might indicate that World Transport Policy and Practice must be counted among the most important journals.

       

      I am grateful to Mr. Oster for giving me opportunity to comment on some of the main points in his statements about our paper (http://www.eco-logica.co.uk/wtpp10.3.pdf). I agree with Mr. Oster that our indicators are not all-comprehensive and that other factors must be taken into account to find the most efficient solution (in economic and/or environmental terms) in every single case. However, there is a need for indicators, which on an aggregated scale (e.g. national, supply chain, company) measures the quantity of transport used to bring products from origin to destination, e.g. from the primary producers to the consumer. If you want to know how logistical decisions influence transport you have to have suitable measures. If you want to reduce the necessary transport and it’s impacts, you have to know where to focus. This is the scope of our paper, as it has been the focal point of several EU-projects (REDEFINE, TRILOG, SULOGTRA), which we have built upon.

       

      The indicators proposed are biased, Mr. Oster claims, to favor ship and rail transport. He is right if you just compare the transport efficiency measure across different transport modes – it will come as no surprise for anyone that in these terms transport by ship is very efficient compared to transport by van. So we do not make this comparison, and stress that efficiency measures must be compared by transport mode. This is what is done in another paper in the same journal (Per Homann Jespersen: The transport content of products) where an example of a transport-LCA (life cycle analysis) is presented.

       

      Comparing within the same transport mode is somewhat simpler. But I must disagree with Mr. Osters statement, that ‘The ratio of ton-kilometers and vehicle-kilometers is equal to vehicle capacity.’ It is, if the vehicles are always full loaded, but they are not, and one of the main issues in reducing freight transport is how to increase the vehicle utilization. For some interesting discussions and data on this, I can refer to the studies made by Prof. McKinnon and colleagues on the food supply chain in the UK (‘Analysis of Transport Efficiency in the UK Food Supply Chain - Full Report of the 2002 KPI survey’, http://www.sml.hw.ac.uk/logistics/pdf/Kpi2003.pdf).

       

      Other papers by my colleagues in the same issue of World Transport Policy & Practice have built on the foundation of the paper discussed here for looking at e.g. a supply chain and a piece if infrastructure. Whether we can continue to develop this approach into something fruitful depends very much on critical comments like Mr. Oster’s pointing at weaknesses and where we have to be more precise in our problem statements. We are grateful for this and hope that others will take up this good example.

       

      Sincerely

       

      Per Homann Jespersen

       

      ---------------------------------------------------------------------------------

      Per Homann Jespersen, Assc.Prof.

      FLUX - Centre for Transport Research

      Dept. of Environment, Technology and Social Studies, Roskilde University

      House P7, P.O.Box 260, DK-4000 Roskilde, Denmark

      Phone +45 4674 2497  Cell phone +45 2449 4295  Fax +45 4674 3041

      mailto:phj@...

       

       

       

       

       

       

       

       

      -----Oprindelig meddelelse-----
      Fra: EcoPlan,
      Paris [mailto:eric.britton@...]
      Sendt: 21. december 2004
      06:55
      Til: 'New Mobility Cafe [NMC]'
      Cc: 'John Whitelegg'; 'Per Homann Jespersen'
      Emne: "World Transport Policy & Practice" Volume 10,Number 3 - Commentary

       

      We post this message here with copies to the editor of World Transport Policy and Practice  and the visiting editor of their special number, thinking that this might lead to some useful discussion?

      *****************************************************************

       

      -----Original Message-----
       On Behalf Of Daryl Oster
      Sent:
      Monday, December 20, 2004 9:42 PM
      To: '
      Asia and the Pacific sustainable transport'

       

      The paper “logistics and transport a conceptual model” (in WTPP v10#3)

      advocates methods that unrealistically reward trains and ships, and obscure

      the advantages of other modes.

       

      On the last quarter of page 9, the definition of the indicator of transport

      “transport efficiency” is defined as the ratio between ton-kilometers and

      vehicle-kilometers. 

       

      This definition may yield efficiency indications with traditional

      transportation modes like ships, trains, and trucks, however it cannot be

      considered a comprehensive measure of efficiency. 

       

      Efficiency has several dimensions, including: 

      Infrastructure cost, Time cost, Labor cost, and Energy cost, all compared on

      a ton-kilometer basis.  Also, there must be a comparison of the distance the

      load travels in vehicles along the routes, compared with the straight-line

      distance from origin to destination that the load is transported (distance

      efficiency).

       

      The ratio of ton-kilometers and vehicle-kilometers is equal to vehicle

      capacity.  So the “logistics and transport a conceptual model” on pg.9

      really states that efficiency scales with vehicle size.   This is only true

      if there are savings in cost associated with vehicle size. 

       

      There are many instances where ton-km costs do NOT scale inversely with

      vehicle size:

       

      *Infrastructure cost – the tooling cost for large vehicles is much greater,

      and the number of vehicles produced is small, so vehicle cost per ton of

      capacity scales with size.

       

      *Time cost – it takes longer to assemble most general cargo loads in large

      vehicles than in small vehicles, so many elements of time cost scale with

      vehicle size. 

       

      *Labor cost – labor savings is one of the main reasons vehicles have

      traditionally been made large.  The use of automation eliminates this

      advantage for large vehicles.  Large vehicles typically have the labor

      disadvantage of requiring several loading and unloading and transfers, and

      the need for storage while waiting for load assembly and disassembly.

       

      *Energy cost – the energy efficiency advantage of using large vehicles is

      mostly related to fluid dynamics.  This advantage is only achieved if the

      vehicle is full, and for travel in a fluid like air or water.  There is no

      advantage if viscosity effects are mitigated (as with ETT – see www.et3.com

      ). 

       

      *The use of large vehicles usually results in a reduction of distance

      efficiency compared with using small vehicles.  Large vehicles are more

      constrained: large ships cannot use small channels, or harbors, increasing

      the distance the load must travel, or involving transfers to other modes;

      trains cannot easily cross mountains or rivers; trucks on a delivery route

      increase the distance the average delivery pallet must travel from the

      origin to the destination. 

       

      The questions raised in the summary on page 10-11:

       

            “Is it possible to divert transport into more environmentally

      friendly    directions, to create sustainable transport solutions or

      even to     create sustainable supply and demand chains?

            Will it be possible to diminish the growth of transport without

      conflicting with welfare goals on the macro level and thereby decouple

      transport and economic growth as was the case in the 1970s in the

      energy sector?

            These questions, however, require some new answers to be given,

      which       means creating new knowledge around transport and its integration in

      the processes of production, distribution and logistics. This paper     has

      tried to move the first steps in that direction by

            presenting some frameworks of analysing the multiple relations

      between     transport and logistics.”

       

      Indicates the intent of the authors are noble, however the methods of

      analysis indicate that either the authors have a shallow understanding of

      transportation efficiency, or they have a hidden agenda of creating policy

      to protect trains and ships from further innovation in transportation

      efficiency promised by automation and new modes.

       

      Daryl Oster

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