128 research outputs found
LEF2 - A strategic freight transport model for Great Britain.
Get PDFINTRODUCTION
This paper reports some innovative model building that yields a useful addition to models of freight in Great Britain. Currently, the Great Britain Freight Model (GBFM) is part of the Department for Transport's (DtT) national
model suite. That model is over-detailed for some purposes and internally only models mode choice effects. Freight modelling requirements in Great Britain were reviewed in work for the DtT, the Strategic Rail Authority (SRA), the
Highways Agency (HA) and Transport for London (TfL). Arising from our work on that project, and our involvement with GBFM, we identified a need for a strategic freight transport model, near instantaneous to run, that could handle both the mode choice effects and market size effects of policies. Section 2 of this paper sets out the background to our work. Section 3 introduces the LEeds Freight Transport (LEFT) model series. Section 4
describes the model LEFT2 from that series, and section 5 gives some results using version LEFT2.6. Section 6 lists the plans we currently have for LEFT3, and section 7 concludes
How highly does the freight transport industry value journey time reliability - and for what reasons?
No full textDelays to road freight vehicles impose a very high cost on the nation. Delayed arrival time can occur for a variety of reasons. This paper presents the findings of a Highways Agency funded study, which has investigated the user valuations of three different kinds of delay:
• A delay resulting from an increased journey time, with fixed departure time
• An increase in the spread (or range) of arrival times for a fixed departure time
• A schedule delay where the departure time is effectively put back.
The paper summarises the findings of the study, which centred on an interview survey of forty shippers, hauliers and third party logistics operators. Respondents were asked to consider one of their freight flows on the trunk road network in detail. Various reasons why respondents value a high degree of predictability of journey times on the trunk road network are identified and discussed. The paper then moves on to present and discuss user valuations of each kind of delay, estimated using the Leeds Adaptive Stated Preference (LASP) methodology
The Development of the LEFT2 Model
Get PDFConstruction of the LEeds Freight Transport Model (LEFT) series was begun as part of the
ITeLS project, although other funding has helped and will take forward its development. The
initial version, now referred to by us as LEFT1, was a simple mode split model intended to
give a rough idea of the magnitudes of the effects of various scenarios, possibly as a way of
filtering which scenarios might be investigated using more detailed models. Besides being
limited to mode split, LEFT1 suffered from a range of minor defects and deficiencies which
led to its abandonment in favour of its successor, LEFT2.
LEFT2 was constructed in 2004 as part of the Engineering and Physical Sciences Research
Council LINK FIT project, ITeLS, funded by the Department for Transport (DfT). We
acknowledge here the help and useful comments from many persons associated with that
project. Besides mode split effects, LEFT2 allows scenarios to alter the total size of the (road
plus rail) market. Its purpose is to provide instantaneous ballpark estimates of road and rail
freight tonne kilometres under various ‘scenarios’. At its base is a desire that the scenarios
should not affect the sum of tonnes moved by both road and rail modes. This was because we
felt that our scenarios should be viewed as having a neutral macroeconomic effect. For
example, if taxes on lorry usage were increased, we would expect other taxes to be lower
than otherwise (or government spending to increase) so that total demand in the economy
would not change. Consumers might buy their goods from closer sources than hitherto, but
they would not be expected to consume less in total. For example, if prices of some goods
rose slightly due to higher road user charges, the consumer would have more to spend due to
offsetting reduced income tax (or whatever) and much the same total quantity would be
bought. Similarly, industrialists as a whole might find input prices increasing slightly, but
will find they can charge slightly more for their outputs.
In summary, LEFT2 provides an instantaneous estimate of the effect of macroeconomically
neutral scenarios on mode split (road, trainload and wagonload), average length of haul and
total market size.
LEFT2 does not load the traffic onto vehicles, and so does not produce magnitudes of HGV
vehicle kilometres, for instance. Consequently it does not produce estimates of emissions or
other nuisances. It is hoped that a future version of LEFT can incorporate these elements and
revisit the other matters that have had to be ‘parked’ for the present. LEFT2 gives a quick
idea of the magnitudes of the effects of any policies that might be considered and should help
to provide a first sift where many policies are being considered.
This report describes the basic LEFT Methodology in Section 2. Emphasis is given to that
methodology actually embodied in LEFT2, but there is also some discussion of rejected
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methodologies, and some that have had to be held over for later versions of LEFT. Section 3
presents additional data that was needed by the LEFT2 model. Section 4 describes the
scenarios chosen for testing in the ITeLS project, while section 5 gives the first results from
using the LEFT2 model, for those scenarios
Where The Black-Eyed Susans Grow
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