Environmental Engineering Reference
In-Depth Information
•
Scenario 2 - Clean mobility or 'satisficing with technology'
: a marked change in terms
of use of low-emission vehicles, but levels of mobility continue to rise and there are no
coordinated efforts to invest in alternatives to the car.
•
Scenario 3 - Sustainable mobility
: here the focus is in developing public transport, walking
and cycling options as well as clean vehicle mobility. Urban structure plays an important
role in shortening trip distances, and there is a reduction in travel by private motor car.
Funding levels change in terms of much higher investment in the non-car modes and the
public realm.
Modelling approach
The scenarios are quantified by modelling the policy packages at each level of application.
This utilises the Central Oxfordshire Transport Model (COTOM), which includes a Saturn-
vehicle/speed CO2 emission factors (Department for Transport, 2008b), modal CO2 emission
factors (Department for Food and Rural Affairs, 2009) and spatial planning assumptions from
the South East Plan (Government Office for the South East, 2009). For all policy packages
and enabling mechanisms the multi-criteria outputs are calculated relative to the BAU reference
case. This leads us to another important but often overlooked issue, namely that the definition
of the BAU is critical to the results in quantified scenario analysis and can take various forms,
including a projection of current trends, a modelled 'current policy approach', or variants in
between. The current policy approach is modelled in the Oxfordshire context.
Appraisal framework
Each scenario is compared relative to its CO2 reduction potential, but also wider multi-criteria
impacts. This is an attempt to show that low carbon transport pathways may have differential
impacts against other policy goals. A multi-criteria appraisal (MCA) framework is thus
developed (
Table 4.5
), with five main elements and the means by which each can be measured.
The core scenarios are explored below in more detail.
Scenario 2: clean mobility or satisficing with technology
This scenario attempts to illustrate the problem of a partial 'satisficing' approach, concentrating
on the technological options of low-emission vehicles and alternative fuels. It assumes a very
successful delivery of these to the mass market to deliver reductions in transport CO2 emissions.
The scenario and results are outlined in
Table 4.6
.
The total CO2 reduction impact is 1,057,932 tCO2 per annum (a 37.4 per cent reduction
relative to the BAU level in 2030). This represents around 2.5 tCO2 per capita in 2030, relative
to a BAU of 4.1 tCO2 per capita in 2030 (and a 2005 transport baseline of 3.8 tCO2 per
capita and target of 1.2 tCO2 per capita). If this level of technological penetration could be
delivered the gains would be very high, but the assumptions are strong, particularly when
compared to current progress in delivering low-emission vehicles in Oxfordshire.
An average vehicle fleet emission level of 95 gCO2/km means the average vehicle in the
fleet by 2030 is similar to the current leading Toyota Prius type technology (89 gCO2/km).
Similar emission gains are expected with LGVs and HGVs. The penetration of alternative
fuels is also ambitious in assumption - 15 per cent alternative fuels (mix of LPG, electric,
biofuel) in the car, 25 per cent in HGVs and 40 per cent in the bus. This strategy is thus sub-
