2 Emissions Projections for the 10 Year Transport Plan

As part of the analysis to inform the Plan, estimates were made of road and rail emissions of oxides of nitrogen (NO_x) and PM₁₀ in 2000 and in 2010 for a number of different scenarios, from a base year of 1996. This work is described in the Background Paper. The scenarios for 2010 considered were as follows:

Firstly a baseline, which assumes that none of the increased investment and other measures in the Plan is implemented. Even in the absence of these measures, a significant decrease in emissions of these two pollutants is expected over this period due to the implementation of tighter standards for emissions from new vehicles and for fuel quality.

The second scenario is described as the ‘Plan’ (see DETR (2000a) and DETR (2000b)) and includes:

• spending and outputs on local transport, London, railways and strategic road;
• during the Plan period the Mayor introduces congestion charging in central London, and local authorities outside London introduce 8 congestion charging and 12 workplace parking levy schemes in the centres of most large urban areas the size of Blackpool and above. All net revenues are recycled into transport improvements in the urban areas concerned
• the impacts on traffic volumes from land use policies, travel plans, sustainable distribution measures and local parking policies.

The projections of road traffic emissions for 2010 were derived using the National Road Traffic Forecasts (NRTF) modelling framework (see DETR, 2000b), incorporating an emissions module based on the National Atmospheric Emissions Inventory (NAEI, Goodwin et al, 1999). The network model in the NRTF framework divides the country into 11 different ‘area types’ and these are listed in Table 2. Emissions estimates for 1996 and projections for 2010 are listed in Table 3.

Table 3. NO_x and PM₁₀ road traffic emissions estimates for 1996 and projections for 2010 (kTonnes, England)

The traffic and emissions projections for the Plan, constant cost and combined scenarios are built up from the results of different policy tests. This is to overcome the point that towns, grouped within the same area type for modelling purposes, may adopt different local transport strategies. For example, some local authorities in large urban areas will build light rail schemes and others guided bus schemes, each with different assumptions on how these schemes are financed. The variations were modelled separately and the resulting projections for the Plan, constant cost and combined scenarios were based on a weighted result. In all, up to five different strategies were tested within an area type. The results of each individual run (for convenience labelled A-E) are presented alongside the weighted result in sections 5 and 6. This weighting process was not used for NRTF area types 1-3 (London). The impact of local policies in London was addressed using the London Transportation Studies (LTS) model, and a combined impact then incorporated in the NRTF model. For the London area types, the forecast emissions under the constant cost and combined scenarios are the same because the combined scenario assumes no increase in the intensity of application of local charging, or effect from limited inter-urban charging, in London.

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