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 (NOx) 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:

A number of illustrative scenarios were also considered. These examine the potential impact of some future changes and policy choices:

Estimates of emissions of NOx and PM10 have been calculated for a total of four scenarios:

The Plan and illustrative scenarios are estimated to reduce traffic emissions of NOx and PM10 relative to the baseline and produce a smaller increase in emissions from rail. Estimates of emissions from road transport and rail are listed in Table 1. A detailed analysis of the impact of reductions in traffic emissions on ambient concentrations has been carried out. The impact of increases in rail emissions on ambient concentrations in 2010 has not been included. The projected reductions in ambient concentrations therefore provide an upper limit on the impact of the Plan measures.

Table 1. 2010 road traffic and rail NOx and PM10 emissions in England (kTonnes) (DETR, 2000b)

NOx

PM10

 

Road

Rail

Total

Road

Rail

Total

Baseline

198

15.4

213

10.5

0.62

11.1

Plan

188

20.5

208

10.1

0.87

11.0

Constant cost

182

23.6

206

9.8

1.01

10.8

Combined

180

23.6

204

9.7

1.01

10.7

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 2. National Road Traffic Forecast area types

Area Type

Description

1

Central London

2

Inner London

3

Outer London

4

Inner Conurbantions

5

Outer Conurbations

6

Other urban areas > 25 km2 area

7

Urban areas 15 - 25 km2 area

8

Urban areas 10 - 15 km2 area

9

Urban areas 5 - 10 km2 area

10

Urban areas < 5 km2 area

11

Rural areas

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

Area Type

1

2

3

4

5

6

NOx 1996

1.92

9.34

29.85

24.00

97.38

26.77

NOx 2010 Baseline

0.67

3.20

9.67

8.01

31.58

8.61

NOx 2010 Plan

0.58

2.73

9.20

7.53

29.09

8.26

NOx 2010 Constant cost

0.56

2.57

8.56

7.38

28.07

8.01

NOx 2010 Combined

0.56

2.57

8.56

7.37

27.36

7.99

PM10 1996

0.131

0.606

1.590

1.386

4.819

1.349

PM10 2010 Baseline

0.043

0.204

0.574

0.481

1.619

0.495

PM10 2010 Plan

0.033

0.164

0.539

0.441

1.491

0.468

PM10 2010 Constant cost

0.031

0.154

0.498

0.433

1.452

0.455

PM10 2010 Combined

0.031

0.154

0.498

0.433

1.417

0.453

Area Type

7

8

9

10

11

Total

NOx 1996

23.46

11.55

16.10

27.69

469.01

737.07

NOx 2010 Baseline

7.33

3.53

5.13

8.57

111.68

197.99

NOx 2010 Plan

7.12

3.42

5.06

8.47

106.87

188.34

NOx 2010 Constant cost

6.92

3.32

4.93

8.24

103.17

181.73

NOx 2010 Combined

6.85

3.30

4.89

8.24

102.40

180.08

PM10 1996

1.154

0.540

0.779

1.316

17.952

31.622

PM10 2010 Baseline

0.423

0.198

0.293

0.487

5.716

10.532

PM10 2010 Plan

0.406

0.191

0.288

0.480

5.593

10.093

PM10 2010 Constant cost

0.396

0.187

0.282

0.470

5.442

9.799

PM10 2010 Combined

0.390

0.186

0.281

0.470

5.411

9.725

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.

Chapter 1           Chapter 3

Report and site prepared by the National Environmental Technology Centre, part of AEA Technology, on behalf of the UK Department of the Environment, Transport and the Regions