Abstract:
The issues of global warming and climate change are a worldwide concern
and the UK government has committed itself to major reductions in CO2
emissions, the most significant of the six greenhouse gases. Road transport
currently accounts for about 22% of total UK emissions of CO2, and has been
steadily rising. Therefore, initiatives are required to try and reduce the gas
emissions in this sector.
The aim of this research has been to develop a computer based vehicle
routing model that calculates the overall amount of CO2 emitted from road
journeys, as well as time and distance. The model has been used to examine
a number of delivery strategies to assess how CO2 emissions vary. The aim
has not been to produce new mathematical theories, but to produce an
innovative basis for routing which will provide new information and knowledge
about how CO2 emissions vary for different minimisation and congestion
criteria.
The approach used in this research brings together elements from
transportation planning and environmental modelling combined with logistics
based vehicle routing techniques. The model uses a digitised road network
containing predicted traffic volumes, to which speed flow formulae are applied
so that a good representation of speed can be generated on each of the
roads. This means that the model is uniquely able to address the issue of
congestion in the context of freight vehicle routing. It uses driving cycle data to
apply variability to the generated speeds to reflect acceleration and
deceleration so that fuel consumption, and therefore CO2, can be estimated.
Integrated within the model are vehicle routing heuristics to enable routes to
be produced which minimise the specified criterion of time, distance or CO2.
The results produced by the model show that there is a potential to reduce
CO2 emissions by about 5%. However, when other transport externalities are
considered overall benefits are dependent on road traffic volumes.
