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Documents

Document history

January 2014: Additions to guidance

All units released IN DRAFT in October 2013 have been added to the guidance.


October 2013: Additions to guidance 'in draft'

Following consultation, the following units have been updated, in some cases with substantial changes, and have now been released ‘in draft’. Some of these units also now contain changes to numerical values.

TAG Unit 1.1D:Introduction to Transport Analysis
TAG Unit 1.3D: Trunk Roads
TAG Unit 1.5D: The Proportionate Update Process
TAG Unit 2.1.1D: The Steps in the Process - Overview
TAG Unit 2.1.2D: Option Development (Stage 1)
TAG Unit 2.1.3D: Further Appraisal (Stage 2)
TAG Unit 2.1.4D: Implementation, Monitoring and Evaluation
TAG Unit 2.2D: Objectives and Problems
TAG Unit 2.4D: Summary Advice on Modelling
TAG Unit 3.1.1D: Introduction to Modelling
TAG Unit 3.1.2D: Transport Models
TAG Unit 3.3.3D: The Air Quality Sub-Objective
TAG Unit 3.3.5D: The Greenhouse Gases Sub-Objective
TAG Unit 3.3.6D: The Environmental Capital Approach
TAG Unit 3.4.1D: The Accidents Sub-Objective
TAG Unit 3.5.6D: Values of Time and Vehicle Operating Costs
TAG Unit 3.5.7D: The Reliability Sub-Objective
TAG Unit 3.10.1D: Variable Demand Modelling – Preliminary Assessment Procedures
TAG Unit 3.10.2D: Variable Demand Modelling – Scope of the Model
TAG Unit 3.10.3D: Variable Demand Modelling – Key Processes TAG Unit
TAG Unit 3.11.2D: Road Traffic and Public Transport Assignment Modelling
TAG Unit 3.15.4D: Rail Passenger Demand Forecasting Methodology

In the following units, which are being released 'in draft', there have been minor changes to the text and changes to numerical values:

TAG Unit 2.7.1D: Transport Appraisal and the Treasury Green Book
TAG Unit 3.2D: Appraisal
TAG Unit 3.3.2D: The Noise Sub-Objective
TAG Unit 3.5.2D:The Transport Economic Efficiency Sub-Objective
TAG Unit 3.5.3D:Transport Benefit Computation
TAG Unit 3.5.4D:Cost Benefit Analysis
TAG Unit 3.5.9D: The Treatment of Costs
TAG Unit 3.9.1D: MSA - Assessment Against Central Government Objectives
TAG Unit 3.9.2D: MSA - Cost Benefit Analysis
TAG Unit 3.9.5D: MSA - Decongestion Benefits
TAG Unit 3.13.1D: Guidance on Rail Appraisal
TAG Unit 3.13.2D: External Costs of Car Use
TAG Unit 3.15.2D: Use of TEMPRO Data
TAG Unit 3.16D: Appraisal in the Context of Housing Development
TAG Unit 3.17D: Social and Distributional Impacts of Transport Interventions
TAG Unit 2.11D has been removed and TAG Unit 1.5D: The Proportionate Update Process has been added.


February 2013: Consultation guidance

The following units in the guidance have been updated for consultation. The consultation period for these documents is expected to continue until at least 17 May 2013. Please see WebTAG Consultations for more details.

TAG Unit 1.3C: Trunk Roads
TAG Unit 2.1.1C: The Steps in the Process - Overview
TAG Unit 2.1.2C: Option Development (Stage 1)
TAG Unit 2.1.3C: Further Appraisal (Stage 2)
TAG Unit 3.1.1C: Introduction to Modelling
TAG Unit 3.1.2C: Transport Models
TAG Unit 3.3.3C: The Air Quality Sub-Objective
TAG Unit 3.3.3C: Pollution Concentration Entry
TAG Unit 3.3.3C: Air Quality Worksheet
TAG Unit 3.3.5C: The Greenhouse Gases Sub-Objective
TAG Unit 3.3.6C: The Environmental Capital Approach
TAG Unit 3.4.1C: The Accidents Sub-Objective
TAG Unit 3.5.6C: Values of Time and Vehicle Operating Costs
TAG Unit 3.5.7C: The Reliability Sub-Objective
TAG Unit 3.10.1C: Variable Demand Modelling – Preliminary Assessment Procedures
TAG Unit 3.10.2C: Variable Demand Modelling – Scope of the Model
TAG Unit 3.11.2C: Road Traffic and Public Transport Assignment Modelling
TAG Unit 3.15.4C: Rail Passenger Demand Forecasting Methodology


August 2012: Additions to guidance

The following units have now been added to the guidance, having previously been released IN DRAFT:
TAG Unit 2.7.2: Appraisal Summary Table
TAG Unit 2.8: Wider Impacts and Regeneration
TAG Unit 3.2: Appraisal
TAG Unit 3.3.2:The Noise Sub-Objective
TAG Unit 3.3.3:The Air Quality Sub-Objective
TAG Unit 3.3.5:The Greenhouse Gases Sub-Objective
TAG Unit 3.4.1:The Accidents Sub-Objective
TAG Unit 3.5.4:Cost Benefit Analysis
TAG Unit 3.5.6:Values of time and Operating Costs
TAG Unit 3.5.9:The Treatment of Scheme Costs
TAG Unit 3.5.14:The Wider Impacts Sub-Objective
TAG Unit 3.6.1:The Option Values Sub-Objective
TAG Unit 3.9.5: Major Scheme Appraisal: Road Decongestion Benefits
TAG Unit 3.10.6:Modelling Smarter Choices
TAG Unit 3.10.7:Modelling Parking and Park-and-Ride
TAG Unit 3.13.1:Rail Appraisal
TAG Unit 3.13.2:External Costs of Car Use in Rail Appraisal
TAG Unit 3.14.1:guidance on the Appraisal of Walking and Cycling Schemes
TAG Unit 3.15.4:Rail Passenger Demand Forecasting Methodology
TAG Unit 3.18: Aviation Appraisal
TAG Unit 3.19: Highway Assignment Modelling


May 2012: Additions to guidance 'In Draft'

Following consultation, the following units have been updated, in some cases with substantial changes, and have now been released ‘In Draft’. They are now expected to become definitive in early August 2012:

TAG Unit 2.8D:Wider Impacts and Regeneration
TAG Unit 3.3.3D:The Air Quality Sub-Objective
TAG Unit 3.3.5D:The Greenhouse Gases Sub-Objective
TAG Unit 3.5.6D:Values of time and Operating Costs
TAG Unit 3.5.14D:The Wider Impacts Sub-Objective
TAG Unit 3.6.1D:The Option Values Sub-Objective
TAG Unit 3.10.6D:
Modelling Smarter Choices
TAG Unit 3.10.7D:Modelling Parking and Park-and-Ride
TAG Unit 3.13.1D:Rail Appraisal
TAG Unit 3.15.4D:Rail Passenger Demand Forecasting Methodology
TAG Unit 3.18D:Aviation Appraisal
TAG Unit 3.19D:Highway Assignment Modelling

In the following units, which are being released IN DRAFT, there have been minor changes to the text and changes to numerical values :

TAG Unit 3.3.2D:The Noise Sub-Objective
TAG Unit 3.4.1D:The Accidents Sub-Objective
TAG Unit 3.5.4D:Cost Benefit Analysis
TAG Unit 3.5.9D:The Treatment of Scheme Costs
TAG Unit 3.9.5D: Major Scheme Appraisal: Road Decongestion Benefits - coming soon
TAG Unit 3.13.2D:
External Costs of Car Use in Rail Appraisal - coming soon
TAG Unit 3.14.1D:
guidance on the Appraisal of Walking and Cycling Schemes

November 2011: Additions to guidance for consultation

The following units have been introduced to replace current guidance units in the Overview and Project Manager tiers, in order to improve its clarity and efficiency to a more targeted audience. They are being released For consultation at this stage:

An Overview of Transport Appraisal

An Overview of Transport Appraisal
guidance for the Senior Responsible Officer (SRO)
guidance for the Technical Project Manager (TPM)

Changes to guidance - restructured guidance for consultation

The following units have been released For consultation:
TAG Unit 3.3.5C: The Greenhouse Gases Sub-Objective
TAG Unit 3.5.6C: Values of time and Operating Costs
TAG Unit 3.10.6C: Modelling Smarter Choices
TAG Unit 3.10.7C: Modelling Parking and Park-and-Ride
TAG Unit 3.13.1C: Rail Appraisal
TAG Unit 3.15.4d: Rail Passenger Demand Forecasting Methodology
TAG Unit 3.19C: Highway Assignment Modelling


August 2011: Changes to guidance

Additions to guidance for consultation
The following unit has been released For consultation:
TAG Unit 3.18C: Aviation Appraisal


April 2011: Changes to guidance

Additions and Changes to guidance

A number of units have been made definitive, having previously been IN DRAFT.

The following units present the new benefit-cost ratio, which changes the treatment of fuel duty and indirect taxation to avoid the undue prioritisation of schemes with high carbon emissions:

TAG Unit 2.5: The Appraisal Process
TAG Unit 2.7.1: Transport Appraisal and the Treasury Green Book
TAG Unit 3.5.1: The Public Accounts Sub-Objective
TAG Unit 3.5.2: The Transport Economic Efficiency Sub-Objective
TAG Unit 3.5.3: Transport Benefit Calculation
TAG Unit 3.5.4: Cost Benefit Analysis

The following unit has new higher values of carbon in line with the values recommended by the Department of Energy and Climate Change.

TAG Unit 3.3.5: The Greenhouse Gases Sub-Objective

The following unit has been updated with separate reporting of journey time changes by size of change per trip:

TAG Unit 3.5.3: Transport Benefit Calculation

Further changes regarding the reporting of journey time have been made in IN DRAFT Units 3.2D and the IN DRAFT Appraisal Summary Table.

guidance on Social and distributional analysis has been added, incorporating a screening stage to ensure proportionate application:

TAG Unit 2.13: Summary guidance on SDIs
TAG Unit 3.3.2: The Noise Sub-Objective
TAG Unit 3.3.3: The Local Air Quality Sub-Objective
TAG Unit 3.4.1:
The Accidents Sub-Objective
TAG Unit 3.4.2: The Security Sub-Objective
TAG Unit 3.5.3: Transport Benefit Calculation
TAG Unit 3.6.2: The Severance Sub-Objective
TAG Unit 3.6.3: The Access to the Transport System Sub-Objective
TAG Unit 3.6.4: The Personal Affordability Sub-Objective
TAG Unit 3.17: SDIs in Transport Interventions

Updated valuations of time and other impacts to reflect the Budget 2011 GDP forecasts:

TAG Noise Spreadsheet (attachment to TAG Unit 3.3.2)
TAG Unit 3.4.1:
The Accidents Sub-Objective
TAG Unit 3.5.6: Values of time and operating costs
TAG Unit 3.5.9: The Treatment of Scheme Costs

guidance on Cost Damping and Realism Testing has been added:

TAG Unit 3.10.2: Variable Demand Modelling - Scope of the Model
TAG Unit 3.10.4: Variable Demand Modelling - Convergence, Realism and Sensitivity
TAG Unit 3.15.5: The Treatment of Uncertainty in Model Forecasting

The TAG Units on Wider Economic Impacts will be renamed "Regeneration" to avoid confusion with "Wider Impacts" in the future.

TAG Unit 2.8.1: Regeneration
TAG Unit 3.5.8: Regeneration Impacts
TAG Unit 3.5.10: Regeneration Worksheet
TAG Unit 3.5.11: Accessibility for Regeneration
TAG Unit 3.5.12: Regeneration Questionnaires
TAG Unit 3.5.13: Regeneration Data Sources

Changes to IN DRAFT guidance

The following Units have been updated in line with Coalition Agreement requirements for reporting impacts:

TAG Unit 3.2D: Appraisal
TAG Unit 2.7.2D: Appraisal Summary Table

Additions to guidance FOR CONSULTATION

Economic values for the analysis of air quality impacts have been produced by the Interdepartmental Group for Costs and Benefits, and accompanied and informed the Air Quality Strategy review in 2006. The approach to valuing changes in air quality for transport schemes is described in this TAG Unit. It is intended that this Unit will eventually replace both TAG Units 3.3.3 and 3.3.4.

TAG Unit 3.3.3C: The Air Quality Sub-Objective


March 2010: Minor changes to 'In Draft' guidance

Additions to 'In Draft' guidance

We have updated Unit 3.5.6D paragraph 1.3.5a and provided two graphs following this paragraph to show how the fuel consumption calculations vary with speed. We have also made some minor changes to clarify Unit 3.10.2D section 1.11 and made some minor changes to headings on Unit 3.10.4D:

TAG Unit 3.5.6D: Values of Time and Operating Costs - 1003
TAG Unit 3.10.2D:
Variable Demand Modelling - Scope of the Model - 1003
TAG Unit 3.10.4D:
Variable Demand Modelling - Convergence, Realism and Sensitivity - 1003


February 2010: Minor changes to 'In Draft' and Definitive guidance

Additions to 'In Draft' guidance

Following feedback, we have made some minor changes to Unit 3.5.6D Tables 3a and 3b, and a minor change to Unit 2.5D paragraph 1.2.12:

TAG Unit 2.5D: The Appraisal Process - 1002
TAG Unit 3.5.6D:
Values of Time and Operating Costs - 1002


January 2010: Minor changes to 'In Draft' and Definitive guidance

Additions to 'In Draft' guidance

We have updated Unit 3.3.5 to include traded and non-traded carbon values to 2010.

TAG Unit 3.3.5D: The Greenhouse Gases Sub-Objective - 1001b

We have made minor updates to the following IN DRAFT units. These updates are restricted to clarification of the guidance and cosmetic changes - the guidance itself is not changed:

TAG Unit 3.4.1D: The Accidents Sub-Objective - 1001b
TAG Unit 3.10.4D:
Variable Demand Modelling - Convergence Realism and Sensitivity - 1001b
and a minor update to Unit 3.15.5 to clarify one of the calculations:
TAG Unit 3.15.5D: The Treatment of Uncertainty in Forecasting - 1001b

We have corrected the IN DRAFT version of "TAG Noise Spreadsheet.xls" (updated 28 January 2010), which can be found with TAG Unit 3.3.2D: The Noise Sub-Objective - 1001b.

Additions to guidance

We have made a correction to definitive Unit 3.14.1, Table 5.

TAG Unit 3.14.1: guidance on the Appraisal of Walking and Cycling Schemes - 1001b


January 2010: Additional 'In Draft' guidance

Additions to 'In Draft' guidance

The following 'In Draft' units replace the previous 'For Consultation' units. In some cases the text has been changed following responses received during the consultation period:

TAG Unit 1.1D: Introduction - 1001
TAG Unit 2.7.1D:
Transport Appraisal and the Treasury Green Book - 1001 (The previous title for this document was 'Transport Appraisal and the New Green Book')
TAG Unit 3.3.2D: The Noise Sub-Objective - 1001
TAG Unit 3.3.3D:
The Local Air Quality Sub-Objective - 1001
TAG Unit 3.4.1D:
The Accidents Sub-Objective - 1001
TAG Unit 3.4.2D:
The Security Sub-Objective - 1001
TAG Unit 3.5.1D:
The Public Accounts Sub-Objective - 1001
TAG Unit 3.5.2D:
The Transport Economic Efficiency Sub-Objective - 1001
TAG Unit 3.5.3D:
Transport Benefit Computation - 1001
TAG Unit 3.5.4D:
Cost Benefit Analysis - 1001
TAG Unit 3.5.9D:
The Estimation and Treatment of Scheme Costs - 1001
TAG Unit 3.6.2D:
The Severance Sub-Objective - 1001
TAG Unit 3.6.3D:
The Accessibility Sub-Objective - 1001
TAG Unit 3.6.4D:
The Personal Affordability Sub-Objective - 1001
TAG Unit 3.10.4D:
Variable Demand Modelling - Convergence Realism and Sensitivity - 1001
TAG Unit 3.15.4D:
Rail Forecasting guidance - 1001
TAG Unit 3.16D:
Appraisal in the Context of Housing Development - 1001
TAG Unit 3.17D:
Social and Distributional Impacts of Transport Interventions - 1001

Following consultation feedback, some of the content of Unit 3.17D has been moved into a separate Project Manager unit. This is being released directly 'In Draft':

TAG Unit 2.13D: Summary guidance on Social and Distributional Impacts of Transport Interventions - 1001

The following 'In Draft' units incorporate some, but not all, of the new guidance in the corresponding 'For Consultation' documents released in September 2009. The 'For Consultation' units (whose unit numbers have the suffix C) remain on the website:

TAG Unit 2.2D: Objectives and Problems - 1001
TAG Unit 2.5D:
The Appraisal Process - 1001
TAG Unit 3.2D:
Appraisal - 1001
TAG Unit 3.10.2D:
Variable Demand Modelling - Scope of the Model - 1001

In the following units, some of the parameters and values have changed. As the guidance in these documents has not changed substantially, they have been released directly in 'In Draft' status:

TAG Unit 3.3.2D: The Noise Sub-Objective - 1001
TAG Unit 3.3.5D:
The Greenhouse Gases Sub-Objective - 1001
TAG Unit 3.4.1D:
The Safety Sub-Objective - 1001
TAG Unit 3.5.6D:
Values of Time and Operating Costs - 1001


October 2009: Consultation guidance

Modifications to guidance 'For Consultation'

Following some early feedback on the documents released 'For Consultation' in September 2009, we have issued the following errata:

Analysis of Monetised Costs and Benefits - 0910 (MS Excel)

TAG Unit 3.10.1C: Variable Demand Modelling - Scope of the Model - 0910
TAG Unit 3.10.3C:
Variable Demand Modelling - Key Processes - 0910


September 2009: Additional Consultation guidance

Additions to guidance 'For Consultation'

A large number of new units have been added to the guidance 'For Consultation'. The consultation period for these documents is expected to continue until at least 1 January 2010. Please see 'Consultation Documents' for more details.

TAG Unit 1.1C: Introduction - 0909
TAG Unit 1.3C: Trunk Roads - 0909
TAG Unit 2.1.1C: The Steps in the Process - Overview - 0909
TAG Unit 2.1.2C: Option Development (Stage 1) - 0909
TAG Unit 2.1.3C: Further Appraisal (Stage 2) - 0909
TAG Unit 2.1.4C: Implementing, Monitoring and Evaluation (Stage 3) - 0909
TAG Unit 2.2C: Objectives and Problems - 0909
TAG Unit 2.4C: Summary Advice on Modelling - 0909
TAG Unit 2.5C: The Appraisal Process - 0909
TAG Unit 2.7.1C: Transport Appraisal and the Treasury Green Book - 0909 (The previous title for this document was 'Transport Appraisal and the New Green Book')
TAG Unit 2.8C: Wider Impacts and Regeneration - 0909
TAG Unit 3.1.1C: Introduction to Modelling - 0909
TAG Unit 3.1.2C: Transport Models - 0909
TAG Unit 3.2C: Appraisal - 0909
TAG Unit 3.3.2C: The Noise Sub-Objective - 0909
TAG Unit 3.3.3C: The Local Air Quality Sub-Objective - 0909
TAG Unit 3.4.1C: The Accidents Sub-Objective - 0909
TAG Unit 3.4.2C: The Security Sub-Objective - 0909
TAG Unit 3.5.1C: The Public Accounts Sub-Objective - 0909
TAG Unit 3.5.2C: The Transport Economic Efficiency Sub-Objective - 0909
TAG Unit 3.5.3C: Transport Benefit Computation - 0909
TAG Unit 3.5.4C: Cost Benefit Analysis - 0909
TAG Unit 3.5.9C: The Estimation and Treatment of Scheme Costs - 0909
TAG Unit 3.5.14C: Wider Impacts - 0909
TAG Unit 3.6.2C: The Severance Sub-Objective - 0909
TAG Unit 3.6.3C: The Accessibility Sub-Objective - 0909
TAG Unit 3.6.4C: The Personal Affordability Sub-Objective - 0909
TAG Unit 3.10.1C: Variable Demand Modelling - Preliminary Assessment - 0909
TAG Unit 3.10.2C: Variable Demand Modelling - Scope of the Model - 0909
TAG Unit 3.10.3C: Variable Demand Modelling - Key Processes - 0909
TAG Unit 3.10.4C: Variable Demand Modelling - Convergence Realism and Sensitivity - 0909
TAG Unit 3.15.4C: Rail Forecasting guidance - 0909
TAG Unit 3.17C: Social and Distributional Impacts of Transport Interventions - 0909


April 2009: WebTAG guidance for 2009/2010

Additions to guidance

The following guidance, which was previously 'In Draft', is now definitive for the financial year 2009/10 and until further notice:

  • TAG Unit 3.3.5: The Greenhouse Gases Sub-objective - 0904 - this is an update of a previous definitive unit with minor alterations to the ‘in draft’ document.
  • TAG Unit 3.3.12: The Physical Fitness Sub-objective - 0904 - this is an update of a previous definitive unit.
  • TAG Unit 3.4.1: The Accidents Sub-objective - 0904 - this is an update of a previous definitive unit with minor alterations to the ‘in draft’ document.
  • TAG Unit 3.5.6: Values of Time and Operating Costs - 0904 - this is an update of a previous definitive unit.
  • TAG Unit 3.5.7: The Reliability Sub-objective - 0904 - this is an update of a previous definitive unit with very minor changes to the 'In Draft' document.
  • TAG Unit 3.14: guidance on the Appraisal of Walking and Cycling Schemes - 0904 - this is a new unit.
  • TAG Unit 3.15.1: Forecasting Using Transport Models - 0904 - this is a new unit.
  • TAG Unit 3.15.2: Use of TEMPRO Data - 0904 - this is a new unit with very minor changes from the 'In Draft' document.
  • TAG Unit 3.15.3: Forecasting and Sensitivity Tests for PT Schemes - 0904 - this is a new unit.
  • TAG Unit 3.15.4: Rail Passenger Demand Forecasting Methodology - 0904 - this is a new unit.
  • TAG Unit 3.15.5: The Treatment of Uncertainty in Model Forecasting - 0904 - this is a new unit.

Additions to 'In Draft' guidance

We have added one new Unit to the 'In Draft' guidance:

  • TAG Unit 2.11D: Strategic Environmental Assessment for Transport Plans and Programmes - 0904

Additions to guidance 'For Consultation'

We have added three new Units to the guidance 'For Consultation':

  • TAG Unit 2.8C: Wider Economic Impacts and Regeneration- 0904
  • TAG Unit 3.5.14C: Wider Economic Impacts - 0904
  • TAG Unit 3.16: Transport Analysis in the Context of Housing - 0904

Future guidance Releases

Further releases planned for 2009 are as follows:

  • guidance on Modelling Freight Movements: A new TAG Unit is being prepared.
  • guidance on the Appraisal of Transport Packages: A new TAG Unit is being prepared.
  • guidance on the Modelling and Appraisal of Smarter Choices:A new TAG Unit is being prepared.
  • guidance on Variable Demand Modelling:These TAG Units are to be updated.
  • guidance on Appraisal for the Tackling Climate Change Goal: New TAG Units are being prepared.

All of these new Units are expected to be released 'For Consultation' initially. We expect them to be revised and released 'In Draft' later in 2009, becoming definitive in April 2010. Please note that we may add to this list, or remove items from it.

Other Changes

The TEMPRO software has been updated. The latest version is TEMPRO v6.1. It incorporates a number of improvements, including a feature to carry out NTM growth forecast automatically.

A new TEMPRO data set, TEMPRO 6, was also due to be released. However, following inspection of this data, it has been decided that TEMPRO 6 will be a consultation version only and the previous TEMPRO 5.4 data set will remain definitive until April 2010. It is expected that a new TEMPRO data set will be produced during 2009, for use beyond April 2010.


December 2008: WebTAG is Moving

In order to rationalise the number of separate websites and domains that the Department maintains, we have integrated the WebTAG website into the DfT domain. For the time being, the look and feel of the WebTAG portal will remain exactly the same, but over the coming months we aim to develop a new WebTAG portal. The new portal will use more modern web technology to improve usability and address some of the concerns raised in the NATA Refresh consultation. The transfer of WebTAG into the DfT domain has in fact already happened - for the last month the WebTAG website has been available at www.dft.gov.uk/webtag, and we are now confident that the integration has been successful and we can continue to offer the same level of service. Consequently we have decided to close the www.webtag.org.uk domain as of January 19, 2009.

This will not affect the functioning of the website but may affect you if you have bookmarked some of the WebTAG units on your browser because these will no longer work once the old (www.webtag.org.uk) domain has been closed. We would therefore advise you to revise your bookmarks now whilst we are running the two systems in parallel.

Additions to 'In Draft' guidance

We have added two new Units to the 'In Draft' guidance:

  • TAG Unit 3.3.12: The Physical Fitness Sub-Objective - 0812 - this Unit has been redrafted to recommend that impacts on Physical Fitness should be monetised if they are significant; and
  • TAG Unit 3.4.1: The Accidents Sub-Objective - 0812 - this Unit now incorporates material formerly published in HEN1.

We have updated the 'In Draft' version of TAG Unit 3.5.6: Value of Time and Operating Costs - 0812, to take account of the latest DECC fuel prices, Fuel Duty and VAT rate changes. A minor amendment has been made to the 'In Draft' version of TAG Unit 3.15.4: Rail Passenger Demand Forecasting Methodology - 0812.

All of these Units are expected to become definitive in April 2009.

Future guidance Releases

The schedule of releases planned for the early part of 2009 is as follows:

  • guidance on the appraisal of wider economic benefits: A new TAG Unit and associated software is being prepared, taking forward the methodology set out in Transport, Wider Economic Benefits and Impacts on GDP.
  • guidance on transport appraisal in the context of housing development: A new TAG Unit is being prepared.
  • guidance on modelling freight movements: A new TAG Unit is being prepared.
  • guidance on the appraisal of transport packages: A new TAG Unit is being prepared.

All of these new Units are expected to be released 'For Consultation' initially. We expect them to be revised and released 'In Draft' later in 2009, becoming definitive in April, 2010. Please note that we may add to this list, or remove items from it.

Other Changes

TEMPRO is being updated. TEMPRO 6 will introduce revised projections, an improved user interface, and greater functionality. Further details will be made available to TEMPRO registered uses during January.

Our software (TUBA, COBA and QUADRO) is being updated to reflect the December 2008 changes to the 'In Draft' version of TAG Unit 3.5.6 (see above) and will be available for use in January.


July 2008: New Release Process and Schedule of Future Releases

Following responses to the NATA Refresh consultation, the Department has established a new release process for NATA guidance. We will only release new and updated definitive guidance (available under guidance Documents on WebTAG) once a year, in April. We will release new and updated guidance 'In Draft' (under 'In Draft guidance' on WebTAG) at least three months before it becomes definitive. 'In Draft' guidance will not be changed significantly before it becomes definitive. Users can, therefore, use 'In Draft' guidance for sensitivity tests or to plan future work with confidence. We will continue to release guidance and other documents for consultation (under 'Consultation Documents'on WebTAG). These documents may change substantially before being released as 'In Draft' guidance. We welcome your involvement in developing these areas of work and your comments on the new release process.

In accordance with the above, all of the guidance Units released now are 'In Draft'. We expect them to become definitive guidance in April 2009. We expect to release a number of other guidance Units later in the year. These will be released 'In Draft' or for consultation. Those released 'In Draft' will become definitive in April 2009. The schedule of releases planned for the rest of 2008 is as follows:

  • guidance on valuation of accidents: TAG Unit 3.4.1 will be updated to include material formerly published in HEN1, Valuation of the Benefits of Prevention of Road Accidents and Casualties.
  • guidance on the appraisal of wider economic benefits: A new TAG Unit and associated software is being prepared, taking forward the methodology set out in Transport, Wider Economic Benefits and Impacts on GDP.
  • guidance on transport appraisal in the context of housing development: A new TAG Unit is being prepared.
  • guidance on modelling freight movements: A new TAG Unit is being prepared.
  • guidance on the appraisal of transport packages: A new TAG Unit is being prepared.

Please note that we may add to this list, or remove items from it.


July 2008: Draft TAG guidance Units on Forecasting

Five new draft TAG Units on forecasting using transport models have been prepared:

  • TAG Unit 3.15.1: Forecasting Using Transport Models - 0807
  • TAG Unit 3.15.2: Use of TEMPRO Data - 0807
  • TAG Unit 3.15.3: Forecasting and Sensitivity Tests for Public Transport Schemes - 0807
  • TAG Unit 3.15.4: Rail Passenger Demand Forecasting Methodology - 0807
  • TAG Unit 3.15.5: The Treatment of Uncertainty in Model Forecasting - 0807

TAG Unit 3.15.1 brings together existing guidance on forecasting from other parts of WebTAG. The Unit provides an overview of the principles of forecasting, model design considerations and the development of the base year, and forecast year reference cases and test scenarios with and without the interventions to be assessed.

TAG Unit 3.15.2 replaces the TEMPRO guidance note that users previously were required to obtain from the TEMPRO download site. This gives guidance on how to use data from the National Trip End Model in transport models of varying degrees of complexity and in cases where an assessment is required without the use of a model.

TAG Unit 3.15.3 replaces the previous TAG Unit 3.11.4 on the specification, development and use of models for major public transport schemes. This Unit gives guidance on the factors pertaining specifically to the supply and demand of public transport schemes, the required forecasting inputs for scenario development and sensitivity testing and dealing with the associated uncertainty.

TAG Unit 3.15.4 replaces the previous Rail Demand Forecasting Methodology provided as an annex to the DfT Value for Money of Franchises guidance. This unit describes the approach to demand forecasting required by the Department for Transport (DfT) for estimating future rail patronage, and should be applied to all DfT Rail and National Networks Group demand forecasting applications.

TAG Unit 3.15.5 is a new Unit that explores in depth how the modeller may deal with uncertain aspects of transport models in order to present robust results. This particularly involves developing sensitivity tests through assessing the likelihood of land use developments in forecast years.


July 2008: Draft TAG guidance Unit on Appraisal of Walking and Cycling Schemes

Walking and cycling schemes potentially offer large benefits to users and the local economy. These include increased fitness through physical activity, safety and environmental benefits that add to journey ambience and the numerous benefits that arise through decongestion such as time savings, reduction in accidents and reduced carbon emissions. Walking and cycling schemes offer a unique challenge to analysts to appraise in a consistent and comprehensive fashion. This TAG Unit follows the guidance consistent with other Units in order to accomplish this, providing reasoned cost-benefit ratios in order to compare potential schemes against one another.

This is the release of the draft guidance on the appraisal of walking and cycling schemes. Consultation for this Unit was completed last year and subsequent developments have been made to the methodology. A primary area of development has been in the appraisal of physical fitness benefits. Adopting the Health Economic Assessment Tool (HEAT) from the World Health Organisation, these benefits are calculated by using a dose-response method for increased activity that reduces the relative risk of frequent users of active modes to all-cause mortality and hence providing a monetary benefit to the economy.

  • TAG Unit 3.14.1: guidance on the Appraisal of Walking and Cycling Schemes - 0807

E-Community on Modelling of Smarter Choices

Meeting our commitment to support innovative solutions for tackling climate change, we have launched an internet-based document-sharing system and forum that will allow us to work collaboratively with the modelling and appraisal community to develop new techniques for modelling smarter travel choice initiatives. Also included in this e-community is the development of the appraisal of walking and cycling schemes.

Users of the e-community are encouraged to upload research articles and material that will increase the knowledge pool of the community and benefit the development of guidance on modelling and appraisal within WebTAG. This forum is open to all registered WebTAG users.

The e-community web site can be found here: www.dft.gov.uk/ecommunities/smarterchoices/.

If you wish to register to become a member of this e-community, please contact the administrator: robin.cambery@dft.gsi.gov.uk.

Release of TEMPRO 5.4 Data Sets

TEMPRO v5.4 data sets are available from the TEMPRO download site at www.dft.gov.uk/tempro.

This data set is an update that incorporates:

  • Expected house building information taken from the most recent regional planning documents and subsequent consultation with regional planning bodies;
  • The most recent sub-national projections of population, households and jobs;
  • The October 2007 release of GAD 2006-based national population projections;
  • Some minor changes to base year employment to rectify some local inconsistencies.

This release incorporates the GAD 2006-based population projections, which indicate a much higher level of population in forecast years. It is anticipated that a subsequent release will be made towards the end of 2008 in order to incorporate updated sub-regional projections of population, households and employment when these become available.

Before downloading the data set, please refer to the Important Information area of the web site. This details the changes made to this data set relative to TEMPRO 5.3 and the status of this data set relative to previous releases and in the context of the new NATA Refresh release schedule. Please also refer to the updated FAQ section of the site if you require assistance with the software or how to use the data, as well as the updated guidance notes.


July 2008: Greenhouse Gases Sub-Objective - Revised

TAG Unit 3.3.5 (The Greenhouse Gases Sub-Objective) has been revised to reflect new Defra advice on the valuation of carbon emissions. In transport appraisals, the new Shadow Price of Carbon method replaces the existing Social Cost of Carbon approach.

  • TAG Unit 3.3.5: The Greenhouse Gases Sub-Objective - 0807

July 2008: Values of Time and Operating Costs - Revised

TAG Unit 3.5.6 (Values of Time and Operating Costs) has been revised to incorporate BERR's central fuel price forecasts. (These are being kept under review and a further edition of 3.5.6 may be released later in 2008). The opportunity has also been taken to include BERR's actual annual average fuel prices rather than the existing April based figures. Also, Table 15 and accompanying text has been redrafted to clarify the treatment of vehicle operating costs for non-work purposes.

  • TAG Unit 3.5.6: Values of Time and Operating Costs - 0807

July 2008: The Reliability Sub-Objective - Revised

TAG Unit 3.5.7 (The Reliability Sub-Objective) has been released as a new 'In Draft' guidance Unit on this topic. This Unit builds on the 'consultation' text released in July 2007. This new Unit will become definitive in April 2009. The new Unit provides guidance on the estimation of monetised estimates of reliability for motorway and dual carriageway schemes and for public transport schemes. This Unit represents the current state of knowledge. This is a rapidly developing area where we are likely to learn from further research, so further revisions to the guidance are likely.

  • TAG Unit 3.5.7: The Reliability Sub-Objective - 0807

October 2007: NATA Refresh Consultation Document

The Department has published a NATA Refresh consultation document alongside, and as part of, its overall transport strategy Towards a Sustainable Transport System: Supporting Economic Growth in a Low Carbon World, responding to the recommendations made in Sir Rod Eddington's Transport Study.

The NATA Refresh consultation document seeks views by 31 March 2008 on how NATA should be developed.

Both documents can be found on the DfT website:

  • Towards a Sustainable Transport System: Supporting Economic Growth in a Low Carbon World
  • The NATA Refresh: Reviewing the New Approach to Appraisal

August 2007: MSA: Road Decongesion Benefits - Revised

TAG Unit 3.9.5 (Major Scheme Appraisal - Road Decongestion Benefits) has been revised. It provides new guidance on the use of estimates of the marginal external costs of adding car traffic to a road in the estimation of decongestion benefits.

  • TAG Unit 3.9.5: MSA: Road Decongestion Benefits - 0708

August 2007: Unit 3.13.1, guidance on Rail Appraisal

Some revisions have been made to the text following feedback. Any further comments should be passed to the contact address given at the end of this Unit.

  • TAG Unit 3.13.1: guidance on Rail Appraisal - 0708

July 2007: Consultation on Travel Time Reliability Advice in WebTAG

The Department has released for consultation draft guidance on the appraisal of travel time reliability.

In the guidance, the impact of a proposal on improving journey time reliability for transport users is assessed, including both passengers and freight. This Unit represents the current state of knowledge. This is a rapidly developing area where we are likely to learn from further research. The recommendations on reliability set out in the Unit are made within the context of what is achievable using the existing knowledge base.

We shall be pleased to receive any comments or suggestions you may have on the material in this unit. Comments received before 26 October 2007 will be taken into consideration when preparing formal guidance on this topic.

  • TAG Unit 3.5.7: The Reliability Sub-Objective - 0707

June 2007: Consultation on Amending Variable Demand Modelling Advice in WebTAG

The Department released guidance on variable demand modelling as WebTAG 2.9 and 3.10 (June 2006) which indicates, among other things, that simple elasticity models should not be used to estimate variable demand modelling responses. However, it suggests that simple elasticity models may be used to narrow down scheme options before a full variable demand model (VDM) is used to establish more detailed effects of the schemes (WebTAG 3.10.3, Paragraph 1.2.4).

Work was commissioned by the Department in March 2006 to look into the validity of this advice in the context of option sifting. The study investigated whether simple elasticity models could be used as a proxy model when the fully-specified VDM model would take a long time to run and a large number of exploratory option tests are required. The research concluded that elasticity models may be used to help rank options to assist in scheme selection, with the proviso that sufficient model convergence is achievable. The report also went on to make a number of recommendations in amending the current guidance.

This consultation invites you to comment (before 21 September 2007) on the recommendations proposed and the Department's response.

  • Consultation on Amending Variable Demand Modelling Advice in WebTAG - 0706 (Adobe Acrobat - 117KB)

May 2007: Refresh of the New Approach to Appraisal

Over the last 40 years the Department has developed a comprehensive approach to the appraisal of transport proposals, such as major road and public transport schemes, based largely on cost-benefit analysis and environmental impact assessment techniques. In 1998 the New Approach to Appraisal was introduced as part of the 1998 Integrated Transport White Paper. This, together with subsequent amendments to NATA over the last few years, is located at the WebTAG web site - www.dft.gov.uk/webtag/.

Although parts of the guidance are updated on a fairly regular basis, the Secretary of State has approved a more strategic refresh of the whole NATA guidance being carried out in anticipation of NATA's 10th anniversary in 2008. The Refresh will form part of the analytical work being taken forward to implement the recommendations made by Sir Rod Eddington and Sir Nicholas Stern in their recent Reviews.

The Refresh will focus on the following areas:

i. the current guidance reflects its road schemes origin and the Refresh will seek to provide improved advice covering proposals relating to all modes of transport, making the guidance more consistent with Eddington's 'mode neutral' stance;
ii. the guidance also reflects a large infrastructure focus. The Refresh will aim to provide clearer integration with guidance on small scale targeted interventions, such as walking and cycling. It will also include advice on the Cabinet Office's new system of Impact Assessments;
iii. the guidance needs to be aligned with DfT's new objectives, including the Department's social and accessibility objective;
iv. improving consistency with other advice, such as the Highways Agency's Design Manual for Roads and Bridges;
v. updating the presentation of the guidance to ensure it continues to provide a coherent and transparent body of expert advice;
vi. the Refresh provides an opportunity to update the price base for which costs and benefits in transport appraisals are expressed;
vii. reflecting the Stern Review, the Refresh provides an opportunity to develop a strategy for making further progress over the next few years on valuing the environmental impacts of transport proposals;
viii. ensuring that summary information about the value for money of a proposal meets decision-making needs, including consideration of how measures such as the Benefit Cost Ratios prioritise across modes;
ix. the Refresh provides an ideal opportunity to make the appraisal guidance more helpful at early stages in scheme development when strategic views about proposals have to be made.

The current guidance represents the best advice for scheme promoters undertaking appraisals in order for the Department to make its decisions while the refresh is underway: its conclusions cannot be anticipated.

Timetable

July - September 2007: proactive discussions with stakeholders, including non-government organisations, academics, scheme promoters, other government Departments and local authorities.
Autumn 2007: a paper, possibly alongside Eddington Response document, on the reasons for, and the main areas covered by, a NATA refresh and initiating a consultative change process.
Winter 2007: review of which changes to the guidance can be implemented as 'quick wins' within refreshed guidance by March 2008 and which changes require a longer term programme of work.
Spring 2008: delivery of 'quick wins' within refreshed guidance for immediate use in detailed appraisals and development of strategic proposals for the 2014-19 period and initiation of longer term programme of work on the guidance.


April 2007: Unit 3.13.2, guidance on Rail Appraisal - External Costs of Rail Use

Unit 3.13.2, guidance on Rail Appraisal - External Costs of Rail Use, has moved from Consultation into guidance. This Unit has been revised to reflect comments received during the consultation period.

  • TAG Unit 3.13.2: guidance on Rail Appraisal - External Costs of Rail Use - 0704

March 2007: guidance on the Appraisal of Walking and Cycling Schemes: Unit 3.14.1

The Department has released for consultation draft guidance on the appraisal of walking and cycling schemes.

Walking and cycling schemes potentially offer large benefits to users and the local economy. These include increased fitness through physical activity, safety and environmental benefits that add to journey ambience and the numerous benefits that arise through decongestion such as time savings, reduction in accidents and reduced carbon emissions. Walking and cycling schemes offer a unique challenge to analysts to appraise in a consistent and comprehensive fashion. This TAG Unit follows the guidance consistent with other Units in order to accomplish this, providing reasoned cost-benefit ratios in order to compare potential schemes against one another.

We shall be pleased to receive any comments or suggestions you may have on the material in this unit. Comments received before 8 June 2007 will be taken into consideration when preparing formal guidance on this topic.

  • TAG Unit 3.14.1: guidance on the Appraisal of Walking and Cycling Schemes - 0703

March 2007: Speed/Flow Relationships in Traffic Models

The Department has published on the DfT website (www.dft.gov.uk/pgr/economics/rdg/speedflowrelationships.pdf) a report prepared by Denvil Coombe that discusses the following issues:

  • Those software packages that offer the ability to model separate speed/flow relationships by vehicle type.
  • The use of speed cut-offs at flows higher than capacity.
  • The convergence of traffic speeds and flows to equilibrium.
  • The non-uniqueness of the routes used by different classes of vehicles.
  • Conversion from vehicles to passenger car equivalents in traffic modelling.

The overall conclusion from his report is that, were the Department to require the use of separate speed/flow relationships for light and heavy vehicles of the DMRB form, modellers could accommodate such a requirement. The need for additional DfT guidance on these topics will be kept under review.


February 2007: Unit 3.13.1, guidance on Rail Appraisal

Unit 3.13.1, guidance on Rail Appraisal, has moved from Consultation into guidance. This Unit has been revised to reflect comments received during the consultation period.

  • TAG Unit 3.13.1: guidance on Rail Appraisal - 0702

February 2007: Unit 3.5.6, Values of Time and Operating Costs

Minor amendments have been made to Unit 3.5.6, Values of Time and Operating Costs.

  • TAG Unit 3.5.6: Values of Time and Operating Costs - 0702

February 2007: Update of Unit 3.6.1: The Option Values and Non-Use Values Sub-Objective

The Department has released for consultation draft updated and expanded guidance on Option Values and Non-Use Values which will supersede the unit published in June 2003. This updates the Strategic Rail Authority appraisal criteria to bring it into line with the current Department for Transport Appraisal guidance.

Option and non-use values are often associated with rail services but in principle are equally applicable to other public transport modes (bus, coach, LRT, underground, air), road infrastructure and to freight facilities (if option values exist for car ownership, they are already internalised in the car ownership decision). Within scheme appraisal, it will be particularly important to consider option and non-use values if the strategies or plans which are being appraised include measures which will substantially change the availability of transport services within the study area (e.g. the opening or closure of a rail service, or the introduction or withdrawal of buses serving a particular rural area).

We shall be pleased to receive any comments or suggestions you may have on the material in this unit. Comments received before the 1 May 2007 will be taken into consideration when preparing formal guidance on this topic.

  • TAG Unit 3.6.1: The Option Values and Non-Use Values Sub-Objective - 0702

February 2007: guidance on Modelling and Appraisal for Road Pricing - Units 2.12, 3.12.1, 3.12.2, 3.12.3, 3.12.4

We have revised the Road Pricing guidance (TAG Units 2.12, 3.12.1, 3.12.2, 3.12.3 and 3.12.4) to reflect the comments we received during the consultation period. Of the five guidance documents, two are unchanged or only marginally altered. In the others, there are changes for clarification, some simplification and improvements to the structure of content.

It is clear that the more advanced parts of the guidance have not yet been used by scheme promoters designing road pricing schemes. Because the draft guidance has not been fully tested, it remains in the Consultation section of the website. The Department welcomes comments on these revised drafts for consideration when the guidance is next revised.


October 2006: The Greenhouse Gases Sub-Objective (Unit 3.3.5); Values of Time and Operating Costs (Unit 3.5.6); The Estimation and Treatment of Scheme Costs (Unit 3.5.9)

The Department has officially released three revised units of guidance:

  • TAG Unit 3.3.5: The Greenhouse Gases Sub-Objective - 0610
  • TAG Unit 3.5.6: Values of Time and Operating Costs - 0610
  • TAG Unit 3.5.9: The Estimation and Treatment of Scheme Costs - 0610

TAG Unit 3.3.5: The Greenhouse Gases Sub-Objective has been revised to incorporate the use of money values in assessing greenhouse gas impacts. The revised guidance requires scheme promoters to estimate the changes in carbon emissions in each year over the life of the scheme and to use these estimates alongside estimates of the money values of reducing emissions in each year to calculate the net present value of the scheme's impact on carbon emissions over the life of the project. The monetary value of the change in emissions over the appraisal period will be reported alongside the existing quantitative assessment as part of the overall assessment of the impact on greenhouse gases. To facilitate this assessment the appraisal software issued by the Department (COBA and TUBA) have been developed to be capable of calculating the money value of the change in carbon emissions and to report it as part of their standard output. The revised guidance describes the calculations included in the appraisal software and explains how the outputs should be reported to the Department.

TAG Unit 3.5.6: Values of Time and Operating Cost has been revised to reflect the latest evidence and forecasts relating to the calculation of vehicle operating costs. In revising the guidance a cubic expression has been introduced to describe the relationship between fuel consumption and average speeds rather than a quadratic expression, as in the current guidance. The use of a cubic expression is consistent with the best available evidence.

TAG Unit 3.5.9: The Estimation and Treatment of Scheme Costs has been revised in light of the Department's recent review of its published guidance on cost estimation. This review was prompted by a number of recent high-profile cases of scheme cost over-runs. The review led to a number of important revisions to the existing guidance that should help to make it clearer to promoters how the Department expects costs to be estimated for use in appraisal and what evidence should be included in the appraisal documentation. More specifically the revised guidance represents an improvement to the Department's guidance in the following ways:

  • It consolidates into one unit all the guidance on estimating scheme costs and preparing them for use in appraisal.
  • It emphasises the need for scheme promoters to factor in realistic assumptions about cost escalation.
  • It provides clearer guidance to promoters on how to handle risk in appraisal (including requiring a quantified risk assessment to be provided for all major schemes).
  • It provides updated guidance on adjusting costs to reflect optimism bias, drawing on the results of the research project on Optimism Bias that was commissioned by the department from Bent Flyvbjerg, whose results were published in 2004, and the latest Green Book.
  • It provides a fully worked example to illustrate the guidance.

The revisions to TAG Unit 3.5.9: The Estimation and Treatment of Scheme Costs have caused the Department to make a number of other changes to its existing guidance in order to eliminate duplication and maintain consistency. The key changes are:

  • Deleting all of the contents of TAG Unit 3.9.3: MSA - Risk Analysis and TAG Unit 3.9.4: MSA - Optimism Bias and replacing with links to the new guidance in TAG Unit 3.5.9.
  • Ensuring that all references to the revised guidance use the revised unit title.

Scheme developers are advised that these three units of guidance should be used to appraise all new options and that the Department will expect all schemes submitted for funding after 1 January 2007 to be consistent with this new guidance.

Existing registered users of the COBA and TUBA appraisal software will automatically be sent revised versions of these programs along with revised user manuals by the Department's consultants. The new programs will incorporate the revisions mentioned in TAG Units 3.3.5, 3.5.6 and 3.5.9 above.


September 2006: guidance on Rail Appraisal: Unit 3.13.1

The Department has released for consultation draft guidance on rail appraisal.

Unit 3.13.1 updates the Strategic Rail Authority Appraisal Criteria to bring it in line with current Department for Transport Appraisal guidance. It is also intended to support those conducting rail appraisals by providing a set of recommended values and assumptions. We would like to invite views on whether the advice is clear and appropriate for the circumstances in which it is to be used.

It is currently in draft and does not represent formal guidance. We will be pleased to receive any comments or suggestions you may have on the material in this Unit. Comments received before 1 November will be considered in preparing formal guidance on this topic.

  • TAG Unit 3.13.1: guidance on Rail Appraisal - 0609

July 2006: guidance on Rail Appraisal: External Costs of Car Use - Unit 3.13.2

The Department has released for consultation draft guidance on estimating external costs of car use in appraisal of rail schemes.

TAG Unit 3.13.2 introduces a new method for estimating the external costs of car use, for general use in rail scheme appraisals. Estimates of the marginal congestion costs of car use have been derived from the Department's National Transport Model and other external costs from the methods developed in 'Surface Transport Costs and Charges' (Sansom, Nash, Mackie, Shires & Watkiss, 2001). We would like to invite views on whether the advice is clear and appropriate for the circumstances in which it is to be used. We anticipate releasing for consultation during September a unit explaining the derivation of these values.

This unit will be followed later in August by a guidance on Rail Appraisal Unit that will bring Rail appraisal into line with the Department's wider appraisal methodology (TAG Unit 3.13.1).

  • TAG Unit 3.13.2: guidance on Rail Appraisal: External Costs of Car Use - 0607

It is currently in draft and does not represent formal guidance. We will be pleased to receive any comments or suggestions you may have on the material in this Unit. Comments received before 1 October will be considered in preparing formal guidance on this topic.


July 2006: guidance on Modelling and Appraisal for Road Pricing - Units 2.12, 3.12.1, 3.12.2, 3.12.3, 3.12.4

The Department has released for consultation draft new guidance on modelling and appraisal for road pricing.

TAG Unit 2.12: Introduction to Modelling and Appraisal for Road Pricing provides an overview of the modelling and appraisal issues, including scheme design and social and distributional issues, arising in the analysis of road pricing schemes. It also provides an outline of the approaches required to address those issues.

More detailed guidance for analysts is provided in TAG Units 3.12.1, 3.12.2, 3.12.3 and 3.12.4:

  • TAG Unit 3.12.1: Designing Effective Road Pricing Schemes - 0607 discusses approaches to the design of effective road pricing schemes;
  • TAG Unit 3.12.2: Modelling for Road Pricing - 0607 provides advice on the modelling of road pricing schemes;
  • guidance on the issues arising when appraising road pricing schemes is provided in TAG Unit 3.12.3: Appraisal of Road Pricing Schemes - 0607; and
  • TAG Unit 3.12.4: Measuring the Social and Distributional Impacts of Road Pricing Schemes - 0607 provides guidance on the use of social research methods to assess the social and distributional impacts of road pricing.

They are currently in draft and do not represent formal guidance. We will be pleased to receive any comments or suggestions you may have on the material in these Units. Comments received before 1 October will be considered in preparing formal guidance on this topic.


June 2006: guidance on Variable Demand Modelling

The Department has officially released new guidance on variable demand modelling. This incorporates minor changes following the consultation exercise between September and December 2005. The one important change made is to the assessment of the need for variable demand modelling. This advice has replaced existing Departmental guidance on Induced Traffic Appraisal (in DMRB 12.2.2) and extends the types of scheme for which the effects of variable demand on scheme benefits and the level of induced traffic has to be estimated quantitatively.

The DIADEM software which enables variable demand models to be set up easily has also been released. This can be obtained from Mott MacDonald. Any questions on the software should be directed to DIADEM@mottmac.com.

The advice should be used forthwith on all trunk road schemes unless a stage has been reached at which in the opinion of the overseeing organisation, its use would result in an unacceptable delay to progress. It is recommended for use for other types of scheme, and will be required for these schemes where public finance is sought and the application will be considered after 1 June 2007.

An overview of the variable demand modelling advice and a description of the underlying principles are set out in TAG Unit 2.9.1: Variable Demand - Overview - 0606 and TAG Unit 2.9.2: An Introduction to Variable Demand Modelling - 0606. This material is aimed at project managers and provides useful background information.

The detailed advice for analysts is provided as four TAG units - TAG Unit 3.10.1: VDM Preliminary Assessment Procedures - 0606 that defines criteria to enable analysts to decide whether the effects of variable demand seriously undermine the justification for their scheme; TAG Unit 3.10.2: VDM Scope of the Model - 0606 gives the guidance required to specify the scope of a variable demand model; the form of variable demand mechanisms and the circumstances when they are suitable to be used are described in TAG Unit 3.10.3: VDM Key Processes - 0606; TAG Unit 3.10.4: VDM Convergence Realism and Sensitivity - 0606 sets out appropriate convergence standards together with the required realism and sensitivity tests needed to provide evidence about the robustness of the model. A further TAG unit of technical appendices will be released at a later date.


February 2006: guidance on Transport Related Noise

The Department has officially released new guidance on transport-related noise impacts. This now includes a method for valuing changes in the noise levels experienced at residential locations in urban areas between the hours of 6am and midnight from road and rail noise. The guidance also includes a noise calculation spreadsheet which automates the calculation of the net present value of noise of the proposed scheme, as well as the estimated change in the number of people annoyed.

The guidance takes forward the research the Department commissioned on the "Valuation of Transport-Related Noise in Birmingham", undertaken by the University of East Anglia, which analysed the differences in the market prices of houses exposed to changing levels of road and rail traffic noise. This study was a part of the Department's wider research programme to broaden the range of monetised impacts within transport appraisal to aid the decision-making process. Work in this area currently includes the study of attitudes to noise from aviation sources, results of which will be reflected in this TAG unit in due course.

Scheme developers are advised that this new guidance should be used to appraise all new options, whilst schemes already being appraised should continue to use the existing guidance. The Department will expect all schemes submitted for funding after the 1st January 2007 to be consistent with this new guidance.

The Department is currently working on updating other areas. We would appreciate your views as to whether you would prefer receiving each update as and when it is available or would rather we waited until a number of updates were available and send them to you as one. Feedback on this issue would be greatly appreciated.


January 2006: Release of guidance on Public Transport Modelling and Forecasting

The Department has released new guidance on Public Transport Modelling and Forecasting. This guidance will replace the Major Scheme Appraisal in Local Transport Plans: Part 3.

An overview of the advice and a description of the underlying principles are set out in the TAG Unit 2.10.1: Introduction to Forecasting Models for Public Transport Schemes - 0601 and the TAG Unit 2.10.2: Introduction to Model Structures for Public Transport Schemes - 0601. This material is aimed at project managers and provides useful background information.

The detailed advice for analysts is provided as four TAG units:

1. TAG Unit 3.11.1: Model Structures and Traveller Responses for Public Transport Schemes - 0601 provides guidance on the structure of appropriate forecasting tools for major public transport schemes including: the necessity of certain model components on the basis of the objectives and likely consequences of the scheme; good practice in the application of the full range of model components; and, the decision-making process for determining model structures, guided by examples of major public transport schemes.

2. TAG Unit 3.11.2: Road Traffic and Public Transport Assignment Modelling - 0601 provides detailed advice on assignment methods for public transport models and covers the following topics: methods of estimating changes in road traffic congestion as a result of a public transport scheme; where to find advice on the development of road traffic assignment models; how to achieve convergence of these models and how they should be validated; the development of public transport passenger assignment models; assignment methods; generalised costs; path building; cost skimming; convergence and validation of public transport passenger assignment models; the design and conduct of travel demand surveys required for public transport model development; the creation of matrices of public transport passenger trips; the responses of public transport operators to changes in demand; and commercial software capabilities.

3. TAG Unit 3.11.3: Mode Choice Models: Bespoke and Transferred - 0601 provides: guidance on the decision of when it may be appropriate to develop a bespoke mode choice model or transfer a demand model and/or any of its components; guidance on the process of developing bespoke mode choice models; Stated Preference design; and procedures for transferring mode choice models where this is appropriate.

4. TAG Unit 3.11.4: Forecasting and Sensitivity Tests for Public Transport Schemes - 0601 that will be completed as soon as The Treatment of Uncertainty in Model Forecasting (a new TAG Unit) has been agreed.

An overview of the advice and a description of the underlying principles are set out in the TAG Unit 2.10.1: Introduction to Forecasting Models for Public Transport Schemes - 0601 and the TAG Unit 2.10.2: Introduction to Model Structures for Public Transport Schemes - 0601. This material is aimed at project managers and provides useful background information.

The detailed advice for analysts is provided as four TAG units:

1. TAG Unit 3.11.1: Model Structures and Traveller Responses for Public Transport Schemes provides guidance on the structure of appropriate forecasting tools for major public transport schemes including: the necessity of certain model components on the basis of the objectives and likely consequences of the scheme; good practice in the application of the full range of model components; and, the decision-making process for determining model structures, guided by examples of major public transport schemes.

2. TAG Unit 3.11.2: Road Traffic and Public Transport Assignment Modelling provides detailed advice on assignment methods for public transport models and covers the following topics: methods of estimating changes in road traffic congestion as a result of a public transport scheme; where to find advice on the development of road traffic assignment models; how to achieve convergence of these models and how they should be validated; the development of public transport passenger assignment models; assignment methods; generalised costs; path building; cost skimming; convergence and validation of public transport passenger assignment models; the design and conduct of travel demand surveys required for public transport model development; the creation of matrices of public transport passenger trips; the responses of public transport operators to changes in demand; and commercial software capabilities.

3. TAG Unit 3.11.3: Mode Choice Models: Bespoke and Transferred provides: guidance on the decision of when it may be appropriate to develop a bespoke mode choice model or transfer a demand model and/or any of its components; guidance on the process of developing bespoke mode choice models; and advice on procedures for transferring mode choice models where this is appropriate.

4. TAG Unit 3.11.4: Forecasting and Sensitivity Tests for Public Transport Schemes that will be completed as soon as a The Treatment of Uncertainty in Model Forecasting ( a new TAG Unit) has been agreed.

The Department has also taken this opportunity to make minor amendments to the following TAG Units; 1.1, 3.1.2, 3.1.3, 3.4.1 and 3.5.6.


September 2005: Consultation on guidance on Variable Demand Modelling and "Public Transport Modelling and Forecasting"

The Department has released draft new guidance on variable demand modelling for consultation. The advice will replace existing Departmental guidance on Induced Traffic Appraisal (in DMRB 12.2.2) and extends the types of scheme for which the effects of variable demand on scheme benefits and the level of induced traffic has to be estimated quantitatively.

An overview of the advice and a description of the underlying principles are set out in TAG Unit 2.9.1: Variable Demand - Overview - 0509 and TAG Unit 2.9.2: An Introduction to Variable Demand Modelling - 0509. This material is aimed at project managers and provides useful background information.

The detailed advice for analysts is provided as four TAG units - TAG Unit 3.10.1: VDM Preliminary Assessment Procedures - 0509 that defines criteria to enable analysts to decide whether the effects of variable demand seriously undermine the justification for their scheme; TAG Unit 3.10.2: VDM Scope of the Model - 0509 gives the guidance required to specify the scope of a variable demand model; the form of variable demand mechanisms and the circumstances when they are suitable to be used are described in TAG Unit 3.10.3: VDM Key Processes - 0509; TAG Unit 3.10.4: VDM Convergence Realism and Sensitivity - 0509 sets out appropriate convergence standards together with the required realism and sensitivity tests needed to provide evidence about the robustness of the model. A further TAG unit of technical appendices will be released at a later date.

The Department has also released draft new guidance on Public Transport Modelling and Forecasting for consultation. This guidance will replace the Major Scheme Appraisal in Local Transport Plans: Part 3.

An overview of the advice and a description of the underlying principles are set out in the TAG Unit 2.10.1: Introduction to Forecasting Models for Public Transport Schemes - 0509 and the TAG Unit 2.10.2: Introduction to Model Structures for Public Transport Schemes - 0509. This material is aimed at project managers and provides useful background information.

The detailed advice for analysts is provided as four TAG units:

1. TAG Unit 3.11.1: Model Structures and Traveller Responses for Public Transport Schemes - 0509 provides guidance on the structure of appropriate forecasting tools for major public transport schemes including: the necessity of certain model components on the basis of the objectives and likely consequences of the scheme; good practice in the application of the full range of model components; and, the decision-making process for determining model structures, guided by examples of major public transport schemes.

2. TAG Unit 3.11.2: Road Traffic and Public Transport Assignment Modelling - 0509 provides detailed advice on assignment methods for public transport models and covers the following topics: methods of estimating changes in road traffic congestion as a result of a public transport scheme; where to find advice on the development of road traffic assignment models; how to achieve convergence of these models and how they should be validated; the development of public transport passenger assignment models; assignment methods; generalised costs; path building; cost skimming; convergence and validation of public transport passenger assignment models; the design and conduct of travel demand surveys required for public transport model development; the creation of matrices of public transport passenger trips; the responses of public transport operators to changes in demand; and commercial software capabilities.

3. TAG Unit 3.11.3: Mode Choice Models: Bespoke and Transferred - 0509 provides: guidance on the decision of when it may be appropriate to develop a bespoke mode choice model or transfer a demand model and/or any of its components; guidance on the process of developing bespoke mode choice models; and advice on procedures for transferring mode choice models where this is appropriate.

4. TAG Unit 3.11.4: Forecasting and Sensitivity Tests for Public Transport Schemes - 0509 that will be completed as soon as a The Treatment of Uncertainty in Model Forecasting ( a new TAG Unit) has been agreed.

The consultation period for both the variable demand modelling and public transport guidance finishes on December 31.

The Department has also taken this opportunity to make minor amendments to the following TAG Units; 1.1, 3.1.2, 3.1.3, 3.4.1 and 3.5.6.


December 2004: Release of Strategic Environmental Assessment guidance

The EU Strategic Environmental Assessment (SEA) Directive came into force on 21 July 2004 and applies to plans and programmes, and modifications to them, whose formal preparation began after 21 July 2004. It also applies to plans and programmes whose formal preparation began before that date, if they have not been adopted (or submitted to a legislative procedure leading to adoption) by 21 July 2006.

Following consultation TAG Unit 2.11: Strategic Environmental Assessment for Transport Plans and Programmes has now been formally released providing guidance on how to carry out the assessment.

Minor changes have also been made to the following TAG units (1.1, 2.1, 2.2, 2.5, 3.3.1, 3.3.5, 3.3.7, 3.3.8, 3.3.10, 3.4.1, 3.5.1, 3.5.6) and to some text on the site.


June 2004: Minor Changes to Value of Time guidance

TAG Unit 3.5.6: Values of Time and Operating Cost - 0406 has been revised to remove some inconsistencies in the data used to derive market price values of time per vehicle.


May 2004: Incorporation of Transport Economics Note, Revision of guidance on Major Scheme Appraisal and Release of Draft SEA guidance for Consultation

TAG has been revised to incorporate and update guidance previously provided by the Transport Economics Note. The major changes can be found in TAG Unit 3.5.4: Cost Benefit Analysis - 0405 and TAG Unit 3.5.6: Values of Time and Operating Costs - 0405. The new guidance provides up to date values for use in appraisals as well as important new advice on appraisal period and the Department's standard base year. TAG Unit 3.9.2: MSA - Cost Benefit Analysis - 0405 has also been updated to reflect these changes.

The other major change to TAG has been the revision of some aspects of major scheme appraisal guidance for local transport schemes. The main changes here include a revised major scheme check list and further guidance on evaluation and monitoring both to be found in TAG Unit 1.4: Major Schemes in Local Transport Plans - 0405. guidance on risk analysis and optimism bias has also been updated, these changes are to be found in TAG Unit 3.9.3: MSA - Risk Analysis - 0405 and TAG Unit 3.9.4: MSA - Optimism Bias - 0405. Specific regeneration advice, MSA: Regeneration (Unit 3.9.7) has been withdrawn to avoid overlap with advice in TAG Unit 3.5.8: The Wider Economic Impacts Sub-Objective - 0405.

The guidance has also been amended slightly to clarify how the impact of schemes on non-UK residents and firms should be treated in appraisals. In cases where such impacts are material to the overall value for money of the scheme, the guidance highlights the need to separate out the impact on non-UK residents from those on UK residents as part of the supporting analysis on Distribution and Equity (See TAG Unit 2.5 and TAG Unit 2.7.1).

The Department has also released draft guidance on strategic environmental assessments as TAG Unit 2.11: Strategic Environmental Assessment guidance for Transport Plans and Programmes - 0405 that can be found on the site in the consultation documents drop down menu.

This document presents draft guidance on how to carry out strategic environmental assessment (SEA) within the framework of the New Approach to Appraisal for transport. It applies to transport plans and programmes including Local Transport Plans (LTPs). The guidance addresses the requirements of European Directive 2001/42/EC on the assessment of the effects of certain plans and programmes on the environment, also known as the SEA Directive.

The Department has also taken this opportunity to make minor amendments to the following TAG Units; 1.1, 3.3.3, 3.5.1, 3.5.2, 3.5.3, 3.5.9, 3.5.11, 3.8.1, 3.9.1 and 3.9.6.


February 2004: Revised Local Air Quality guidance

The local air quality assessment procedure for input to the Appraisal Summary Table has been updated. TAG Unit 3.3.3: The Local Air Quality Sub-Objective - 0402 has been revised to reflect this. An spreadsheet is available to carry out the required calculations. Minor changes have also occurred to other TAG Units (2.5, 2.6, 2.7.2, 3.1.2, 3.2, 3.3.4, 3.3.5, 3.3.10 and 3.5.11) and to some text on the site.


September 2003: guidance on preparing an Economic Impact Report

The Department published Steer Davies Gleave's final report guidance on preparing an Economic Impact Report in August, 2003. As planned, the guidance set out in that report has now been added to the Transport Analysis guidance website. An introduction for Project Managers is provided in TAG Unit 2.8: guidance on Preparing an Economic Impact Report - 0309, with guidance for the Expert User being given in TAG Unit 3.5.8: The Wider Economic Impacts Sub-Objective - 0309.

Updated: January 2014