Review - Adding capacity at Heathrow Airport: Implications for emissions
by P Tomlinson, P Emmerson, K Turpin and I S McCrae
UNPUBLISHED PROJECT REPORT
UPR/IE/33/08
Centre for Sustainability at TRL Limited /UNPUBLISHED PROJECT REPORT UPR/IE/33/08
Version: 1.1
Review - Adding capacity at Heathrow Airport: Implications for emissions
By P Tomlinson, P Emmerson, K Turpin and I S McCrae
Client: Val Beale and Rob Gibson
London Borough of Hillingdon, London Borough of Hounslow
Copyright TRL Limited, 13 February 2008
This report has been prepared for the London Borough’s of Hillingdon and Hounslow of behalf of the 2M Group, is unpublished and should not be referred to in any other document or publication without the permission of the London Borough’s of Hillingdon and Hounslow. The views expressed are those of the authors and not necessarily those of the London Borough’s of Hillingdon and Hounslow.
ApprovalsProject Manager / K Turpin
Quality Reviewed / I S McCrae
If this report has been received in hard copy from TRL, then in support of the company’s environmental goals, it will have been printed on recycled paper, comprising 100% post-consumer waste, manufactured using a TCF (totally chlorine free) process.
Contents Amendment Record
This report has been issued and amended as follows;
Version / Date / Description / Editor / Technical referee1 / 12/02/08 / Draft for internal review / P Tomlinson / I McCrae
1.1 / 13/02/08 / Draft for client review / K Turpin / I McCrae
CONTENTS
Executive Summary i
1 Introduction 1
2 Macro Issues 2
2.1 Demand for Air Travel 2
2.2 What is the Origin of the Demand? 3
2.3 Aviation Emissions 4
2.3.1 Meteorological Factors 6
3 Surface Transport 7
3.1 Do Minimum Forecasts 7
3.2 Transport Modelling Practice and Assumptions 7
3.2.1 Air Passenger Travel Demand Forecasting 7
3.2.2 Surface Transport Modelling 8
3.2.3 Mode Split Assumptions 9
3.2.4 HGV Forecasting 11
3.2.5 Travel Cost Assumptions 11
3.2.6 Journey Time 12
3.2.7 Forecasting Periods 13
3.2.8 Local Road Network 14
4 Different Road User Groups 15
4.1 Air Passenger Surface Transport 15
4.1.1 Kiss-and-Fly 15
4.1.2 Car Parking 15
4.2 Employee Traffic 16
4.3 Airport Business and Goods Service Vehicles 16
4.4 Airside Surface Traffic 16
4.5 Non-Airport Traffic 16
5 Emissions and Air Quality Modelling 18
5.1 ADMS Air Pollution Model 19
5.2 Mitigation Strategies 20
5.2.1 HGV Charging 21
5.2.2 Area-wide Road Pricing 21
5.2.3 Car Parking 21
5.2.4 Packaged Approach 22
6 References 23
Executive Summary
The Government and BAA propose adding a third runway north of the existing A4. This runway is currently envisaged to have an operational length of 2,200 metres, some 200 metres longer than the earlier proposals. Associated with this development, an additional passenger terminal would be provided which would reduce the need for aircraft to taxi across the existing northern runway. The development of this sixth terminal may thus be seen as central to the overall aim of adding capacity to Heathrow Airport
The third runway could accommodate a mix of all but the largest four-engined aircraft and allow the airport to handle around 700,000 air transport movements (ATMs) a year, nearly 50 per cent more than today. The Government and BAA believe that full mixed mode operation (540,000 ATMs) by 2015 would be compatible with compliance with the EU air quality limits for PM10, and NO2 within the vicinity of the airport without the need for further mitigation measures. The 2M Group, a body representing Local Government Authorities surrounding the airport, has taken up the challenge of examining the robustness of the forecast effects of the proposed expansion upon the transport network, regional emissions and local air quality. The Transport Research Laboratory (TRL Limited) and Air Quality Consultants (AQC) have been appointed to support the undertaking of this examination.
Whilst it is accepted that the DfT consultants have attempted to undertake an appropriate assessment, it is apparent that the consultation documentation raise a large number of wide ranging questions. In general terms the documentation is not written in a style which might be easily understood by the general public – who after all those that might be directly impacted by the proposed developments. In addition, the consultation documentation fails to provide sufficient background information to allow an in-depth evaluation of the robustness of the Governments assessment and conclusions. Therefore, this review by TRL raises a number of observations and questions, in an attempt to improve the consistency and opaqueness of the approach.
Undoubtedly all environmental impact assessments, in so far as they attempt to predict future conditions, rely on a range of estimates and assumptions made by technical experts. However, it is inappropriate not to recognise that these predictions are subject to uncertainty, and that this uncertainty increases with an increasing time horizon. Therefore, any environmental impact assessment must consider these uncertainties centrally within any resulting conclusions. This review attempts to identify areas of uncertainty and the associated assumptions that have been made, and critically reviews these to ascertain if they have been treated in a balanced and clear manner. This has resulted in the identification of a number of questions that the Government and BAA should address as part of this consultation.
This review identified a range of questions, the most significant of which are listed below.
Macro scale issues:
· How was the forecast number of flights arrived at? Was it based on modelling the competition between airports to arrive at the market share Heathrow would achieve and then translated into the different aircraft numbers and type, or was the forecast based upon trend projections of aircraft types operating from Heathrow in isolation?
· Can a general description of London Airports Surface Access Model (LASAM) and its base assumptions be provided to include consideration of competition from other airports and choice of flight times?
· What is the cause of the increased trip-length for AM peak and inter-peak leisure car use to Heathrow? Does this suggest an increase in the distance in which leisure travellers take car based trips to Heathrow (i.e. the same or fewer vehicles but over a greater distance), or an increase in the number of vehicles over shorter distances?
· How have the forecasts for leisure and business car based travel addressed the consequences of the housing growth areas in the South East and neighbouring regions?
· How has the number of flights been determined for each of the modelled years? Does this represent maximum capacity or is it a forecast of actual flight numbers?
· What assumptions have been used to forecast aircraft emission rates? What sensitivity analysis has been undertaken around assumptions in the future aircraft mix and emission rates?
· What is the worst case use pattern for the third runway and has this been modelled?
Surface transport:
· Can the Government/BAA provide a table illustrating the actual and relative contribution of each surface transport emission source to the air quality forecasts for the existing, do minimum and future year forecasts?
· Can the Government/BAA provide a response as to why a full analysis was not undertaken examining the benefits of allowing for greater optimisation in existing current operations?
· Can traffic data be provided which substantiates the significant increase in road travel and furthermore how these data have been applied in the traffic assignment modelling process in terms of trip matrices?
· Given the synthesizing of the base year position in the Regional Road Traffic Model (RRTM) and the lack of objective means to judge the realism of its forecasts, what error range might be envisaged and what are the results of the sensitivity analysis upon emissions forecasts?
· How were the diurnal traffic flow profiles attributed to the road network where no traffic data were collected and which roads were grouped as non-motorway Heathrow area or as part of the strategic network?
· Given the night time traffic flows in the Heathrow area, why were trip matrices not then developed for this period to inform the RRTM?
· Describe how automatic traffic count data was validated in terms of vehicle classifications.
· Please provide a full explanation as to how vehicle speeds were derived by RRTM including any relevant speed/flow curves and equations and how the speeds were then validated for each link of the one-to-one model road network.
· What effect does the variable quality of the traffic model in representing journey times have on the source or extent of emissions that are generated?
· How has optimising of traffic signals been implemented where conflicts may exist between prioritising different traffic flows, those of maintaining the journey times of public transport and other issues of public safety and pedestrian accessibility? How sensitive are the emissions forecasts to changes in the manner that signals are optimised?
· Has a sensitivity analysis been undertaken on the assumption that no increase in highway capacity would be provided?
Different road user groups
· Are the employee forecasts in relation to passenger throughput correct in showing that high levels of productivity improvement are required? To what extent is it likely that such productivity improvements can be delivered?
· Provide the necessary traffic data for each proposed scenario in which to assess the relative differences affecting non airport traffic levels?
Emissions and air quality modelling
· Supporting evidence that the quality of the models does not compromise the results, is required from the Government/BAA?
· What emission factor datasets were used in estimating landside road transport emissions and what was the rationale for their selection?
Finally, it should be noted that whilst the use of inappropriate fleet compositions and associated emissions can lead to errors in the overall assessment, traffic data in terms of flows remains a consistent weakness in all environmental impact assessments. The recent experiences on the Thames Gateway highlight this issue, and particularly demonstrate the difficulties of predicting flows and demands into the future.
1
1
1 Introduction
The Government and BAA propose adding a third runway at London’s Heathrow (LHR) Airport, to the north of the existing A4. This runway is envisaged to have an operational length of 2,200 metres (m), approximately 200 m longer than the original proposal. An additional passenger terminal would be provided with direct access to existing rail services, designed to meet the needs of air passengers and airline alliances under mixed mode operations (both long-haul and short haul traffic). The development of this new terminal, which would be in addition to the new Terminal 5, would reduce the need for aircraft to taxi across the existing northern runway. The development of the new runway and the new supporting terminal are thus interlinked.
The runway would accommodate a mix of all but the largest four-engined aircraft and could potentially enable the airport to handle around 700,000 air transport movements (ATMs) a year, an increase of nearly 50% over the current level of activity.
The consultation also presents proposals for introducing mixed mode on the existing two runways, either with or without additional ATMs, as an interim measure ahead of a third runway development.
The Government and BAA believe that full mixed mode (540,000 ATMs) by 2015 would be compatible with compliance with the EU air quality limits for PM10, and NO2 in the vicinity of the airport without the need for further mitigation measures. This contrasts with earlier air quality evaluations that took place prior to the DfT’s Project Sustainable Development of Heathrow (PSDH), which estimated significant areas of air quality limit value exceedance. In part, as a result of the PSDH process, a revised air quality impact assessment has been undertaken, based upon revisions to the air quality modelling procedures and associated tools. The Government and BAA now conclude that air quality is no longer an issue with the operation and proposed developments at LHR.
In exploring the robustness of the approach taken by the Government and BAA it is worth noting that the ability to distinguish between the private sector promoter and Government as arbiter appears confused within the consultation documents. Thus it is left to others to critically review the evidence that has been provided by the Government and BAA.
The 2M Group has taken up the challenge of examining the robustness of the forecast effects of the expansion upon emissions and air quality, not least given the exceedances that currently occur close to the M4 motorway. TRL and Air Quality Consultants (AQC) have been appointed to undertake this examination.
This review of the documentation has resulted in a diverse range of issues on which clarification is sought, and thus it is necessary to bring a structure to them to provide advice to the 2M Group. This report commences with the Macro issues before considering the implications for road and aircraft based emissions.
Undoubtedly all environmental impact assessments, in so far as they attempt to predict future conditions, rely on a range of estimates and assumptions made by technical experts. However, it is inappropriate not to recognise that these predictions are subject to uncertainty, and that this uncertainty increases with an increasing time horizon. Therefore, any environmental impact assessment must consider these uncertainties centrally within any resulting conclusions. This report attempts to identify areas of uncertainty and the associated assumptions that have been made, and critically reviews these to ascertain if they have been treated in a balanced and clear manner. This has resulted in the identification of a number of questions that the Government and BAA should address as part of this consultation. A colour coding has been applied to these various questions, which relates to our view as to their relative importance within this environmental assessment process. These issues range from ’pink’ for high importance, ’yellow’ for medium importance and ‘green’ for low importance.
2 Macro Issues
At the outset it is evident that there are two distinct issues associated with emissions. The first are those associated with greenhouse gas (GHG) emissions and the second are those associated with emissions of PM10 and NOx. The former raises issues of a policy nature while the latter are associated with legal constraints.