DD362
Postwick Hub Scheme Economic Appraisal Report
April 2013 Norfolk County Council
Postwick Hub Scheme Economic Appraisal Report 233906
BSE
NOR
DS-20
P1
http://pims01/pims/llisapi.dll?func=ll&objId=1514790521&objAction=brow se&viewType=1 29 April 2013
April 2013
Norfolk County Council
County Hall, Norwich
Mott MacDonald, County Hall, Martineau Lane, Norwich NR1 2US, United Kingdom t +44 (0)1603 767530, W www.mottmac.com
Postwick Hub Scheme - Economic Appraisal Report
Issue and revision record Revision P1
Date 29.04.2013
Originator I Conway S Sirivadidurage
Checker C White A Gordon (Reviewer)
This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose.
Approver G Kelly
Description For publication
We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it.
Mott MacDonald, County Hall, Martineau Lane, Norwich NR1 2US, United Kingdom t +44 (0)1603 767530, W www.mottmac.com
Postwick Hub Scheme - Economic Appraisal Report
Content Chapter
Title
Page
Executive Summary
1
1.
Introduction
2
1.1 1.2
Background ________________________________________________________________________ 2 Purpose and Layout of Report __________________________________________________________ 3
2.
Transport Economic Appraisal
4
2.1 2.2 2.3 2.4 2.5 2.6
Overview __________________________________________________________________________ Modelling Framework_________________________________________________________________ Do Minimum Assumptions _____________________________________________________________ Do Something Network _______________________________________________________________ Postwick Hub Scheme Costs ___________________________________________________________ Postwick Hub Scheme Analysis of Monetised Costs and Benefits ______________________________
4 5 6 6 6 7
3.
Transport Scheme Costs for Economic Appraisal
8
3.1 3.2 3.3 3.4 3.5 3.6
Scheme Costs ______________________________________________________________________ Conversion from Financial Year to Calendar Year __________________________________________ Adjustment for Construction Inflation _____________________________________________________ Application of Optimism Bias ___________________________________________________________ Maintenance Costs __________________________________________________________________ Operating Costs _____________________________________________________________________
8 8 8 9 9 9
4.
Transport User Benefits Economic Appraisal Results
13
4.1 4.2 4.3 4.4
Overview _________________________________________________________________________ Transport Economic Efficiency ________________________________________________________ Public Accounts ____________________________________________________________________ Analysis of Monetised Costs and Benefits________________________________________________
13 13 15 15
5.
Analysis of Transport User Benefits and Robustness of the Economic Appraisal
17
5.1 5.2 5.3 5.4
Total User Benefits by Time Period _____________________________________________________ User benefits by WebTAG time and distance bands ________________________________________ Reliability and Stability of the Economic Appraisal Results ___________________________________ Warnings in the TUBA Appraisal _______________________________________________________
17 17 18 20
6.
Accident Benefits
21
6.2 6.3 6.4 6.5 6.6
Data Sources ______________________________________________________________________ Traffic growth rates _________________________________________________________________ Network structure and link flows _______________________________________________________ Junction assessment ________________________________________________________________ Results Summary___________________________________________________________________
21 22 22 22 22
7.
Gross Value Added & Development Benefits
24
7.1 7.2
GVA:_____________________________________________________________________________ 24 Development benefits: _______________________________________________________________ 26
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Postwick Hub Scheme - Economic Appraisal Report
7.3
Development Costs _________________________________________________________________ 28
8.
Conclusions
Appendices Appendix A. A.1. A.2. A.3. A.4. A.5. A.6. A.7. A.8. Appendix B. B.1. B.2. B.3. B.4. B.5. B.6. Appendix C. C.1. C.2. C.3.
Annualisation Factors________________________________________________________________ Annualisation Factors________________________________________________________________ Selection of Count Sites______________________________________________________________ Calculation of average flows __________________________________________________________ Designation of Weekday Hours ________________________________________________________ Designation of Saturday, Sunday and Bank Holiday hours as Inter-peak or Off-peak ______________ Calculation of Annualisation Factors ____________________________________________________ Journey Purpose Splits for Weekend Time Periods ________________________________________ Weekend Adjustment for Freight _______________________________________________________ TUBA Setup _______________________________________________________________________ Demand __________________________________________________________________________ Skims ____________________________________________________________________________ Current, Modelled and Appraisal Years __________________________________________________ User Classes ______________________________________________________________________ Demand and Skim Matrix Factors ______________________________________________________ Skim Factors ______________________________________________________________________ TUBA and COBA Warnings ___________________________________________________________ Summary of TUBA Warnings __________________________________________________________ Investigation of serious TUBA warnings _________________________________________________ COBA Warning Messages ____________________________________________________________
29
30 31 31 31 33 34 35 36 36 37 39 39 39 40 40 41 41 42 42 42 43
Tables Table 2.1: Table 3.1: Table 3.2: Table 3.3: Table 3.4: Table 3.5: Table 3.6: Table 3.7: Table 4.1: Table 4.2: Table 4.3: Table 5.1: Table 5.2: Table 5.3: Table 5.4: Table 5.5: Table 6.1: Table 7.1: Table 7.2: Table 7.3: Table 7.4:
Demand Segments __________________________________________________________________ 6 Scheme Costs - £(2012 Q3 Prices) _____________________________________________________ 10 Scheme Costs by Calendar Year £(2012 Q3 Prices) _______________________________________ 10 Calculation of Constant Price Adjustment Factor __________________________________________ 11 Scheme Costs after Adjustment for Construction Inflation- £(2012 Q3 Prices)____________________ 11 Scheme Costs After Application of Optimism Bias £(2012 Q3 Prices)__________________________ 12 Maintenance Costs and Cost Profile (2013 Q1 Prices) ______________________________________ 12 Summary of Operating Costs (2007 Q3 Prices) ___________________________________________ 12 Economic Efficiency of the Transport System (TEE) ________________________________________ 14 Summary of Public Accounts __________________________________________________________ 15 Analysis of Monetised Costs and Benefits________________________________________________ 16 Total User Benefit by Time Period ______________________________________________________ 17 Net total user benefits by time saving bands (£000) ________________________________________ 17 Net total user benefits by distance bands (£000) __________________________________________ 17 Total User Benefits as a Proportion of Total User Costs _____________________________________ 18 Demand and Assignment Model Convergence (% GAP) ____________________________________ 19 Accident assessment summary ________________________________________________________ 23 GVA calculation steps for BGBP and LF business developments______________________________ 25 Summary of Planning Gain ___________________________________________________________ 27 TEC Summary _____________________________________________________________________ 27 Derivation of BGBP & LF Developments Benefits __________________________________________ 28
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Postwick Hub Scheme - Economic Appraisal Report
Table A.1: Table A.2: Table A.3: Table A.4: Table B.1: Table B.2: Table B.3: Table B.4: Table B.5: Table B.6: Table B.7: Table B.8: Table C.1:
Annualisation Factors________________________________________________________________ Designation of October Saturday 07:00 - 19:00 Hours ______________________________________ Calculation of Annualisation Factors ____________________________________________________ Freight Weekend Demand Adjustment Factors ____________________________________________ Highway Demand Segmentation _______________________________________________________ Public Transport Demand Segmentation _________________________________________________ Summary of Highway Skims __________________________________________________________ Summary of Public Transport Skims ____________________________________________________ TUBA User Classes _________________________________________________________________ Vehicular Conversion of OGV User Class ________________________________________________ Unit Conversion of Highway Skims _____________________________________________________ Unit Conversion of Public Transport Skims _______________________________________________ Summary of TUBA Warnings __________________________________________________________
31 36 36 38 39 39 39 39 40 41 41 41 42
Local Accident Data in the vicinity of Postwick Junction (2007 – 2012) _________________________ Map showing ATC Sites used for production of Annualisation Factors __________________________ October Daily Profile for ATC Sites _____________________________________________________ October Weekday Profile for ATC Sites__________________________________________________ October Saturday Profile for ATC Sites __________________________________________________ Map showing ATC Sites used for production of Freight Annualisation Variation Factors ____________
21 32 33 34 35 37
Figures Figure 6.1: Figure A.1: Figure A.2: Figure A.3: Figure A.4: Figure A.5:
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Postwick Hub Scheme - Economic Appraisal Report
Executive Summary The Postwick Hub Scheme is a Local Authority Major Project promoted by Norfolk County Council (NCC) to provide a highway capacity improvement and thus help enable employment and residential development proposals to be implemented. NCC is the local highway authority, though it requires orders to be promoted by the Highways Agency (HA) as the A47 at Postwick is a Trunk Road, for which the Secretary of State is the Highway Authority. A Public Inquiry into the Postwick Hub scheme will take place in 2013 and this document contains the economic assessment of the Postwick Hub scheme without the NDR. The proposed Broadland Gate and Laurel Farm employment developments are considered to be dependent upon the construction of the Postwick Hub scheme, due to the inability of the existing local road network to cope with the forecast vehicle trip generation of the development. The transport scheme has been appraised in isolation, without the inclusion of the dependent developments, following the Department for Transport (DfT) WebTAG guidance in 3.16D. Results are presented for the economic impact of the development based on the benefits of land use development as well as the additional Gross Value Added (GVA) benefits of enabling 5000 jobs at Broadland Gate and Laurel Farm. A summary of the results of this appraisal are shown below. Table:
Summary costs and benefits Cost £m
Development Transport scheme
1
Benefits £m
Development Cost : 88
GVA: 378 Development benefits: 494
Present Value of Costs: 25
Present Value of Benefits: -74 Accidents: -4
2010 prices discounted to 2010 1. This is the estimate by NCC's developer partner for Broadland Gate, development costs for Laurel Farm will be additional to this figure.
When tested in isolation, the Postwick Hub scheme is predicted to generate transport disbenefits of £74m and accident disbenefits of £4m. Offsetting the transport disbenefits shown above is a development benefit of £494m, which represents the benefit of the change in traffic patterns caused by the Broadland Gate development. In addition to this, and assessed using the approach in A47 Wider Economic Benefits, Mott MacDonald (2012), is an additional Gross Value Added (GVA) gain of £378m to the local economy. All values are in 2010 prices discounted to 2010. 233906/BSE/NOR/DS-20/P1 29 April 2013 http://pims01/pims/llisapi.dll?func=ll&objId=1514790521&objAction=browse&viewType=1
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1. Introduction 1.1
Background
1.1.1
The Postwick Hub Scheme is a Local Authority Major Project promoted by Norfolk County Council (NCC) to provide a highway capacity improvement and thus help enable employment and residential development proposals to be implemented. NCC is the local highway authority, though it requires orders to be promoted by the Highways Agency (HA) as the A47 at Postwick is a Trunk Road, for which the Secretary of State is the Highway Authority.
1.1.2
The highway scheme was the subject of a joint hybrid planning application submitted to Broadland District Council (BDC). The joint application consisted of an outline planning application for the Broadland Gate Business Park (BGBP) development (to be developed by NCC's developer partner) and a full planning application for proposed highway improvements to upgrade the Postwick Hub junction.
1.1.3
The planning application was originally submitted in December 2008 for a scheme which included twin eastbound diverge slip roads. Revised application documentation was submitted between August and November 2009 for a modified application that closed the existing eastbound diverge slip road due to safety concerns. Planning permission was granted in April 2010 and ultimately re-granted in October 2011 following a judicial review.
1.1.4
Funding approval for the Postwick Hub Scheme and the Northern Distributor Road was sought in 2011 through the Department for Transport’s Development Pool process. A business case was developed and submitted in accordance with the guidance in the Treasury Green Book. Ministerial decisions were made in December 2011 to award funding.
1.1.5
Independently of the Scheme, NCC has developed proposals to extend the existing Postwick Park and Ride site located on the southern side of the A47. These proposals to extend the existing Park and Ride site were the subject of a separate planning application submitted to NCC, and planning permission was granted in May 2010. NCC has commenced this development for the purpose of implementing the planning permission. Delivery of the consented extension of the parking facilities at the Postwick Park and Ride site will follow at a later date (currently projected to be 2015).
1.1.6
The delivery of the Postwick Hub Scheme requires the making of Slip and Side Roads Orders. The Orders are required to enable changes to the existing road layout at the junction. The Secretary of State has requested that a Public Inquiry is held to consider the Orders which will be held later this year. Originally the Public Inquiry was due to commence at the end of September 2012, but its start was postponed and will now commence in July 2013.
1.1.7
Subject to the satisfactory completion of the statutory procedures and a decision by the Secretary of State to make the Orders, works for the implementation of the Postwick Hub Scheme are programmed to commence in early 2014.
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1.2
Purpose and Layout of Report
1.2.1
This report presents the economic appraisal for Postwick Hub and focuses on the monetised impacts of the scheme. The report sets out to provide: An assessment of transport user economic benefits for consumer and business users from the Postwick Hub scheme based on the Variable Demand Modelling (VDM) forecasts during the assessment period; An assessment of the benefits associated with the implementation of the Broadland Gate development considered to be dependent on the Postwick Hub transport scheme. This is assessed as the planning gain associated with the proposed development and the effect the new jobs would have on local Gross Value Added (GVA); The report also discusses the calculation of accidents benefits.
1.2.2
This report contains the following sections after the current introductory section: Section 2 – discusses the transport economic appraisal process followed and any assumptions that have been made; Section 3 – describes the derivation of transport scheme costs for inclusion in the economic appraisal Section 4 - presents the results of the transport economic appraisal and discusses the levels of user benefits that are reported for the scheme; Section 5 – reviews the robustness, reliability and stability of the transport economic results, as required by WebTAG; Section 6 – presents results from accident benefits analysis; Section 7 – discusses planning gain and Gross Value Added benefits. Section 8 – conclusions.
1.2.3
Supporting information is included in a number of appendices: Appendix A – describes the calculation of annualisation factors adopted for the appraisal; Appendix B – describes in detail the TUBA setup; and Appendix C – documents the analysis of TUBA warnings.
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2. Transport Economic Appraisal 2.1
Overview
2.1.1
The transport economic appraisal has been undertaken using the TUBA (Transport Users Benefit Appraisal) program Version 1.9.1 which carries out an economic appraisal in accordance with published DfT guidance. TUBA implements elements of the Sugden method as described in Unit 3.5.3 of WebTAG and undertakes matrix-based appraisal taking trip, time, distance and toll/charge matrices from the transport model as inputs. Based on these trip and cost matrices from the traffic model, TUBA calculates user benefits discounted to the present value year (2010) and produces results for various degrees of disaggregation and summarises the outputs.
2.1.2
Assumptions for the economic appraisal including economic parameters and annualisation factors that form inputs to the TUBA economic appraisal process are discussed in Appendices A, B and C. The key assumptions that have been made in the appraisal are as follows: The Postwick Hub scheme will be opened in 2015 and is appraised over a 60 year period from the year of opening. User benefits of the scheme after the design year of 2030 assume a flat profile and are subject to the normal discounting to 2010 present value year and changes to Values of Time (VoT) and other economic parameters. The economic benefits of the Postwick Hub scheme are accrued over all days of the year (including weekends, bank holidays and over night) although the transport model does not specifically model weekends and bank holidays. How this is done is discussed in Appendix A. This methodology is identical to that used for the 2011 Best and Final Funding Bid submitted to Department for Transport for The Norwich Northern Distributor Route. The scheme will be developed and funded by the public sector and investment costs are subject to optimism bias of 15% reflecting the level of certainty at orders publication stage. The economic appraisal has been carried out for a Core Scenario, which has been developed in line with WebTAG. The land use and development assumptions in the Core Scenario are consistent between the Do Minimum and Do Something, with the exception being the Broadland GateBusiness park (BGBP) and Laurel Farm (LF) employment developments, which are considered to be dependent on the Postwick Hub scheme being approved. Changes in journey times and any economic benefits that are calculated are based on differences between the Do Minimum core scenario and the Do Something scenario. The main economic analysis is based on matrices from variable demand modelling assignments which makes allowance for the effects of destination choice, mode-choice and trip frequency. The impacts of the various demand modelling responses are considered in detail in the Traffic Forecasting Report.
2.1.3
In accordance with guidance on dependent development set out in WebTAG 3.16D, the economic appraisal was carried out in two parts, as follows: Assessment of the Postwick Hub transport scheme in isolation. Assessment of the planning gain associated with the Broadland Gate development.
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2.2
Modelling Framework Forecast Years
2.2.1
Future year traffic forecasts have been developed for three years: 2015, 2020 and 2030.
2.2.2
The future year of 2015 represents the opening year of the proposed Postwick Hub highway scheme with 10% of the dependent developments in place. Whilst the conditions of planning permissions of the dependent developments restrict occupancy of floor space until the highway improvement is operational, and the actual build rate and take up depends on market demand, for assessment purposes it has been assumed that 10% of floor space would be occupied in the opening year.
2.2.3
2020 has been forecast with half of the full dependent developments occupied.
2.2.4
2030 has been forecast 15 years after the opening of the highway scheme with the full extent of the dependent developments occupied. This is the usual design year for highway schemes and the year for which environmental appraisals are required. It will also capture the completion of the JCS. Time Periods
2.2.5
The highway and public transport assignment models have been developed for three time periods: AM Peak Hour (0800-0900hrs) Average Inter-Peak Hour (1000-1600hrs) PM Peak Hour (1700-1800hrs)
2.2.6
The AM and PM peak hour demand matrices are derived from peak period matrices, 0700-1000 hrs for the AM peak period, and 1600-1900hrs for the PM peak.
2.2.7
An Off-Peak model representing an average hour for the period 1900 to 0700 hrs, has also been developed for the purposes of demand modelling, where costs are required for all times of the day (it should be noted that this is not a fully validated model). Demand Segmentation
2.2.8
Highway demand has been segmented into 12 user classes covering all journey purpose and vehicle combinations. This level of segmentation is required for demand modelling purposes. For some purposes fixed and variable demand segments are also separately identified, where fixed demand segments relates to origin destination movements that will not be subject to variable demand modelling; and variable demand segments contain origin destination movements that will be subject to variable demand modelling. Those movements not subject to variable demand modelling are ‘external to external’ movements that it was deemed would not be subject to demand responses from the impact of the Postwick hub scheme.
2.2.9
Public transport demand matrices represent the same personal trip proposes as the highway matrices, and these are then further segmented by car availability. For public transport
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assignment, purpose matrices are combined to form three user group matrices: commute, employers business and other. The user classes are shown in Table 2.1. Table 2.1:
Demand Segments
User class
Vehicle Type
Description
Demand Model Segment
1
Car/ LGV/PT
Work
HBW HBEB
2
Car/ LGV/PT
Employers Business
NHBEB
3
Car/ LGV/PT
Other
HBO NHBO
4
LGV
Freight
Freight (LGV)
5
HGV
Freight
Freight (OGV)
2.3 2.3.1
Do Minimum Assumptions A Do Minimum (DM) scenario is required as a reference upon which to assess the economic effects of the proposed scheme measures. As such it includes schemes and measures that have been implemented between 2006 (the model base year) and 2012 and those post-2012 changes to the existing transport system classified as ‘near certain’ or ‘more than likely’ in accordance with TAG Unit 3.15.5. Thus, the DM includes: Network changes - junction improvements, pedestrian improvements and traffic management and safety schemes within Norwich. Public transport changes - it is assumed that the public transport network remains as it is in the base year. Assumptions have been made in terms of how bus and rail fares change in the future. Overall, it should be noted that there are no major changes to the public transport network in the Do Minimum. Completed housing and business developments.
2.3.2
2.4
A full description of the Do Minimum including location plans of Do Minimum schemes is given in the Traffic Forecasting Report.
Do Something Network
2.4.1
The Do Something (DS) network comprises the Do Minimum network with the Postwick Hub Scheme added to it.
2.4.2
A plan of the Postwick Hub Scheme is contained in the Traffic Forecasting Report.
2.5 2.5.1
Postwick Hub Scheme Costs Base costs for construction, land, preparation, supervision, road maintenance and operation, including an allowance for risk were provided by Norfolk County Council (NCC) together with
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spend profiles. These costs have been modified for economic appraisal in line with WebTAG guidance. Further details on the Postwick Hub Scheme costs can be found in Chapter 3.
2.6
Postwick Hub Scheme Analysis of Monetised Costs and Benefits
2.6.1
The analysis of monetised costs and benefits compares the monetised costs of the scheme against the benefits of the scheme over a 60 year appraisal period. This takes into account the following cost and benefits: Construction costs Maintenance costs Operating costs Changes in journey times Changes in vehicle operating costs Private sector provider benefits Changes in greenhouse gas emissions User charges (e.g. parking charges) Accidents
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3. Transport Scheme Costs for Economic Appraisal 3.1
Scheme Costs
3.1.1
Total scheme costs sub divided by construction, land, preparation, and supervision during construction were provided by Norfolk County Council (NCC). These consisted of base costs including an allowance for contingencies and an allowance for risk calculated from a Quantified Risk Assessment (QRA). All costs were presented in 2012 Quarter 3 prices.
3.1.2
Preparation costs that have already been incurred and that are to be incurred up to the point where a ‘go-ahead’ decision is scheduled to take place are considered to be sunk costs and therefore do not form part of the appraisal, in accordance with guidance set out in WebTAG 3.5.9. Land costs include Part 1 claims.
3.1.3
A summary of scheme costs is provided in Table 3.1. For input to the economic appraisal the costs need to be adjusted to: Convert from financial year to calendar year Take into account construction inflation Reflect Optimism Bias
3.1.4
These processes are discussed in further detail below.
3.1.5
The resultant scheme costs after the application of these processes are presented in Table 3.5.
3.2
Conversion from Financial Year to Calendar Year
3.2.1
Information provided by NCC is by financial year whereas TUBA requires input by calendar year. Costs have been converted to calendar year using professional judgement.
3.2.2
The resulting costs in calendar years is shown in Table 3.2.
3.3
Adjustment for Construction Inflation
3.3.1
Construction inflation has been assessed at 2% per annum for the years 2013 to 2016. This level of construction inflation was used for the 2011 Best and Final Funding Bid submitted to the Department for Transport for the Norwich Northern Distributor Route. The use of 2% was agreed with the County Council’s appointed contractor and is considered appropriate for the following reasons: Construction inflation has probably peaked; Due to overall market conditions, contractors are finding it easier to negotiate with their supply chain to obtain discounts; Ability to use buying power of a large organisation to obtain best value from the supply chain and this would reduce exposure to increased costs; There are a number of inflation-related risk allowances already included within the budget.
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3.3.2
BCIS and other relevant construction inflation indices show forecast construction inflation to be at a lower level than forecast background inflation from RPI over the 2012 to 2016 period (source: Table M3: Medium Term Forecasts for CPI and RPI, HM Treasury Document, May 2012).
3.3.3
As forecast construction inflation is less than the forecast of RPI, scheme costs for input to TUBA need to be adjusted by a constant price adjustment factor. The derivation of the constant price adjustment factor is shown in Table 3.3 and the effect of construction inflation on the construction costs is shown in Table 3.4.
3.3.4
The constant price adjustment factor is applied to construction costs only as this is taken to vary from the RPI which is used for land, preparation and supervision costs.
3.4
Application of Optimism Bias
3.4.1
At previous Programme Entry in December 2009 an Optimism Bias of 25% was employed. For this submission a lower Optimism Bias of 15% has been adopted to reflect the further development that has been completed since Programme Entry. This is consistent with values recommended in WebTAG 3.5.9 for a highway scheme at orders publication stage and is considered to be justified as the level of uncertainty has reduced as a result of the following: Detailed design of the Postwick Hub Scheme has been completed and corresponding provisional target costing received from NCC’s contractor. Planning Permission for the Postwick Hub Scheme has been reconfirmed.
3.4.2
Final costs for inclusion in TUBA are presented in Table 3.5.
3.5
Maintenance Costs
3.5.1
Maintenance Costs and profile were provided by NCC. Maintenance costs assume resurfacing works for the whole of scheme at 15 year intervals. Road maintenance costs have been assumed to increase in line with retail price inflation and therefore no construction price adjustment factors have been applied. Optimism bias has been applied at 15% to all relevant costs. All prices are in 2007 Q3 prices. The assumed maintenance costs are shown in Table 3.6.
3.6
Operating Costs
3.6.1
Operating costs associated with the scheme have been split into: Landscaping costs Street lighting costs Structures Maintenance costs
3.6.2
Operating costs have been annualised from costs received for a 15 year period and have been applied equally to each year of the appraisal. Optimism bias has not been applied to operating costs. All costs have been provided in 2007 Q3 prices
3.6.3
Table 3.7 shows the profile of operating costs received from Norfolk County Council.
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Table 3.1: Type
Construction
Land
Preparation
Supervision
Scheme Costs - £(2012 Q3 Prices) Item
2012/13
2013/14
2014/15
2015/16
2016/17
Total
Cost
-
1,980,556
7,877,501
7,877,501
-
17,735,558
Risk Allowance
-
63,840
287,280
287,280
-
638,400
Total Construction
-
2,044,396
8,164,781
8,164,781
-
18,373,958
Cost
-
-
-
-
163,000
163,000
Risk Allowance
-
-
-
-
-
-
Total Land
-
-
-
-
163,000
163,000
Cost
-
1,208,500
320,000
235,000
-
1,763,500
Risk Allowance
-
76,188
342,846
342,846
-
761,880
Total Preparation
-
1,284,688
662,846
577,846
-
2,525,380
Cost
-
-
250,000
250,000
-
500,000
Risk Allowance
-
-
-
-
-
-
Total Supervision
-
-
250,000
250,000
-
500,000
-
3,329,084
9,077,627
8,992,627
163,000
21,562,338
Total
Table 3.2:
Scheme Costs by Calendar Year £(2012 Q3 Prices)
Type Construction
Land
Item
2013
2014
2015
2016
Total
Cost
-
7,888,682
9,846,876
-
17,735,558
Risk Allowance
-
279,300
359,100
-
638,400
Total Construction
-
8,167,982
10,205,976
-
18,373,958
Cost
-
-
-
163,000
163,000
Risk Allowance
-
-
-
-
-
Total Land Preparation
Cost Risk Allowance Total Preparation
Supervision
-
-
163,000
163,000
542,125
315,000
-
1,763,500
57,141
276,182
428,558
-
761,880
963,516
818,307
743,558
-
2,525,380
Cost
-
250,000
250,000
-
500,000
Risk Allowance
-
-
-
-
-
Total Supervision Total
906,375
-
250,000
250,000
-
500,000
963,516
9,236,288
11,199,534
163,000
21,562,338
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Table 3.3:
Calculation of Constant Price Adjustment Factor 2012
Construction cost increase (p.a.) RPI increase (p.a.)
2013
2014
2015
2016
2.00%
2.00%
2.00%
2.00%
3.10%
2.80%
3.10%
3.10%
Cumulative adjustment factor (constr cost)
1.000
1.020
1.040
1.061
1.082
Cumulative adjustment factor (RPI)
1.000
1.031
1.060
1.093
1.127
Constant price adjustment factor
1.000
0.989
0.982
0.971
0.961
Table 3.4:
Scheme Costs after Adjustment for Construction Inflation- £(2012 Q3 Prices)
Type Construction
Land
Preparation
Item
2013
2014
2015
2016
Total
Cost
-
7,743,780
9,562,877
-
17,306,656
Risk Allowance
-
274,170
348,743
-
622,913
Total Construction
-
8,017,950
9,911,620
-
17,929,569
Cost
-
-
-
163,000
163,000
Risk Allowance
-
-
-
-
-
Total Land
-
-
-
163,000
163,000
Cost
906,375
542,125
315,000
-
1,763,500
57,141
276,182
428,558
-
761,880
963,516
818,307
743,558
-
2,525,380
Cost
-
250,000
250,000
-
500,000
Risk Allowance
-
-
-
-
-
Total Supervision
-
250,000
250,000
-
500,000
963,516
9,086,256
10,905,177
163,000
21,117,949
Risk Allowance Total Preparation Supervision
Total
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Table 3.5:
Scheme Costs After Application of Optimism Bias £(2012 Q3 Prices)
Type
Item
Construction
Land
Preparation
2013
2014
2015
2016
Total
Cost
-
8,905,347
10,997,308
-
19,902,655
Risk Allowance
-
315,295
401,054
-
716,350
Total Construction
-
9,220,642
11,398,362
-
20,619,005
Cost
-
-
-
187,450
187,450
Risk Allowance
-
-
-
-
-
Total Land
-
-
-
187,450
187,450
Cost
1,042,331
623,444
362,250
-
2,028,025
65,712
317,609
492,841
-
876,162
1,108,043
941,052
855,091
-
2,904,187
Cost
-
287,500
287,500
-
575,000
Risk Allowance
-
-
-
-
-
Total Supervision
-
287,500
287,500
-
575,000
1,108,043
10,449,195
12,540,954
187,450
24,285,642
Risk Allowance Total Preparation Supervision
Total
Table 3.6:
Maintenance Costs and Cost Profile (2013 Q1 Prices)
Cost
Cost (£)
Base Cost
60,000
Optimism Bias
9,000
Total
69,000 4,140,000
60 Year Appraisal Period Maintenance Costs Costs
Table 3.7:
Summary of Operating Costs (2007 Q3 Prices)
Item
Cost (£)
Annual Landscaping
1,130
Annual Street Lighting
10,982
Annual Structures Maintenance
10,241
Total Annual Operating Costs
22,353 1,341,180
60 Year Appraisal Period Operating Costs
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4. Transport User Benefits Economic Appraisal Results 4.1 4.1.1
Overview The economy objective identified within WebTAG is concerned with improving the economic efficiency of transport and the efficiency of economic activities, with the key aim of supporting sustainable economic activity and returning good value for money. It considers the following three sub-objectives: To get good value for money in relation to impacts on public accounts; To improve transport economic efficiency for business users and transport providers; To improve transport economic efficiency for non-business consumer users;
4.2
Transport Economic Efficiency
4.2.1
The results of the assessment of user benefits are shown in the TEE table which is presented in Table 4.1. All values quoted are in 2010 prices, discounted to 2010. The TEE table shows that the Postwick Hub scheme is predicted to produce total transport economic efficiency disbenefits of £75m in the 60 year assessment period.
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Table 4.1:
Economic Efficiency of the Transport System (TEE)
Item
Benefit (£000s)
Consumer - Commuting user benefits -13,493
Travel Time
-1722
Vehicle operating costs
333
User charges
0
During Construction & Maintenance
-14,883
NET CONSUMER - COMMUTING BENEFITS Consumer - Other user benefits
-11,592
Travel Time
2,244
Vehicle operating costs
264
User charges
0
During Construction & Maintenance
-9,084
NET CONSUMER - OTHER BENEFITS Business Impacts
-44,076
Travel Time
-6,783
Vehicle operating costs
19
User charges
0
During Construction & Maintenance
-50,840
Sub Total Private Sector Provider Impacts
-489
Revenue Operating costs
0
Investment costs
0
Grant/subsidy
0 -489
Sub Total Other business Impacts
0
Developer contributions
-51,329
NET BUSINESS IMPACT TOTAL Present Value of Transport Economic Efficiency Benefits (TEE) All monetary values expressed in 2010 prices discounted to 2010
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4.3 4.3.1
Table 4.2:
Public Accounts The values presented in Table 3.5 are input into TUBA which converts to the common price base of 2010 and discounts values to 2010. The values in Table 3.6 and Table 3.7 are also converted to a 2010 price base and discounted to 2010 and combined to be presented as operating costs in the Summary of Public Accounts in Table 4.2 below. In addition to the scheme investment and operating costs, the table includes any changes in revenues, including indirect taxes. Summary of Public Accounts
Item
Cost (£000s)
Local Government Funding 122
Revenue Operating Costs
2,280
Investment Costs
5,000 0
Developer Contributions
0
Grant/Subsidy Payments
7402
NET IMPACT Central Government Funding: Transport
0
Revenue
0
Operating costs
17,784
Investment costs Developer Contributions
0
Grant/Subsidy Payments
0 17,784
NET IMPACT Central Government Funding: Non-Transport
-1,772
Indirect Tax Revenues TOTALS Broad Transport Budget
25,186
Wider Public Finances
-1,772
All monetary values expressed in 2010 prices discounted to 2010
4.4
Analysis of Monetised Costs and Benefits
4.4.1
Table 4.3 presents the analysis of monetised costs and benefits.
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Table 4.3:
Analysis of Monetised Costs and Benefits
Item
(£000s) -196
Greenhouse Gases
-14,883
Economic Efficiency: Consumer Users (Commuting)
-9,084
Economic Efficiency: Consumer Users (Other) Economic Efficiency: Business Users and Providers
-51,329
Wider Public Finances (Indirect Taxation Revenues)
1772 -73,720
Present Value of Benefits (PVB)
25,186
Broad Transport Budget Present Value of Costs (PVC) OVERALL IMPACTS
-98,906
Net Present Value (NPV)
-2.927
Benefit to Cost Ratio (BCR) All monetary values expressed in 2010 prices discounted to 2010
4.4.2
The results show that the Present Value of Benefits (PVB) is estimated to be -£74m and the Present Value of Costs (PVC) is estimated to be £25m. The Benefit Cost Ratio (BCR) is -2.9.
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5. Analysis of Transport User Benefits and Robustness of the Economic Appraisal 5.1 5.1.1
Table 5.1:
Total User Benefits by Time Period Table 5.1 shows total user benefits by time period. This shows that the Postwick Hub scheme has an impact on user benefits in all time periods with the greatest total user disbenefits occurring in the PM peak period. Total User Benefit by Time Period
Time Period
Annualisation
Total User Benefit (£m)
Weekday AM
244
-6,342
Weekday PM
475
-26,645
Weekday Inter Peak
2059
-23,045
Weekday Off Peak
2992
-9,891
Weekend (all hours)
4605
-8,884
All monetary values expressed in 2010 prices discounted to 2010
5.1.2
5.2
Weekend disbenefits are derived from outputs from both the off peak and inter peak models. The allocation of weekend hours to the inter peak and off peak modelled time periods is presented in Appendix A.
User benefits by WebTAG time and distance bands
5.2.1
In line with current WebTAG requirements we have examined distance bands and time bands within which user benefits fall.
5.2.2
Table 5.2 shows that the majority of the user disbenefits occur for trips involving small changes in travel times of up to 2 minutes, whereas the majority of benefits derive from larger time savings of more than 5 minutes.
5.2.3
Table 5.3 shows that user benefits are sensibly distributed over distance bands.
Table 5.2:
Net total user benefits by time saving bands (£000) -5 to -2
Time saving bands All user benefits (£000s)
Table 5.3: Distance Bands All user benefits (£000s)
-2 to 0
0 to 2
2 to 5
5mins
Total
-5,200
-35,162
-132,251
36,154
6,678
54,974
-74,807
Net total user benefits by distance bands (£000) Up to 5 kms
5 to 10 kms
10 to 15 kms
15 to 20 kms
20 to 50 kms
50 to 100 kms
>100 kms
Total
-448
-3,706
-15,046
-10,341
-29,597
-8,478
-7,189
-74,805
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5.3
Reliability and Stability of the Economic Appraisal Results
5.3.1
WebTAG requires that the economic results are robust and stable based on stability ratios. The impact of transport model convergence noise should be shown to be minimal. In order to do this the demand/supply model convergence (%GAP) is compared against the proportion of user benefits relative to total costs in the appraisal as calculated in TUBA. A ratio of 10 between the two values, ie %GAP and proportion of user benefits / user costs, is recommended in WebTAG.
5.3.2
Table 5.4 shows the total user benefits as a proportion of total do-minimum user costs.
Table 5.4:
Total User Benefits as a Proportion of Total User Costs 2020
Mode Road
2015 -0.18%
2030 -0.18%
-0.11%
5.3.3
One requirement for robust transport economic appraisal is that iterative demand and assignment models are well converged. The demand and assignment model convergence statistics are shown in Table 5.5.
5.3.4
For Scenarios A and C the demand model convergence ‘gap’ statistics are between 0.09% and 0.14%, within the WebTAG target of 0.2%, for all peaks and the three forecast years.
5.3.5
Similarly, for all peaks and for all forecasting years and for both scenarios, the assignment model convergence ‘gap’ is within the recommended WebTAG value of 0.1% by a substantial margin, generally about ten times less that the target. The measurements of flow and cost changes also exceed the 98% target in most cases: the flow changes all meet the 98% target but the cost changes in 2020 and 2030 AM peak just fail to meet this, but are still above 97% in all cases.
5.3.6
The ‘gap’ measures the proximity to an equilibrium solution for the iterative assignment process and the flow and cost changes measure the stability of the solution, from one iteration to another. The above shows that the demand model and the assignment model compare well with the WebTAG targets and it is considered that all of the model runs are well converged for the purposes of appraising transport economics.
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Table 5.5:
Demand and Assignment Model Convergence (% GAP) 2015
Time Period
Demand model (Target = 0.2%)
Assignment model (% GAP Target = 0.1%)
Assignment model (% Flows Target = 98%)
Do-Minimum Scenario A
0.14
N/A
AM
-
0.012
98.7
IP
-
0.0021
PM
-
0.011
OP
-
0
Do-Something Scenario C
0.10
N/A
AM
-
0.017
98.7
IP
-
0.0017
99.3
PM
-
0.012
OP
-
0
2020 Assignment model (% Costs Target = 98%)
Demand model (Target = 0.2%)
Assignment model (Target = 0.1%)
0.12
N/A
98.1
-
0.011
99.0
99.7
99.7
-
0.0024
98.8
98.4
-
0.0097
99.9
100.0
-
0
0.09
N/A
98.0
-
0.015
98.6
99.5
-
0.0019
99.1
98.9
98.3
-
0.016
99.9
100.0
-
0
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Assignment model (% Flows Target = 98%)
2030 Assignment model (% Costs Target = 98%)
Demand model (Target = 0.2%)
Assignment model (Target= 0.1%)
Assignment model (% Flows Target = 98%)
Assignment model (% Costs Target = 98%)
0.14
N/A
98.0
-
0.017
98.7
97.3
99.2
99.5
99.0
98.4
-
0.0038
98.7
99.5
-
0.0084
99.3
98.8
100.0
100.0
-
0
99.9
100.0
0.10
N/A
97.8
-
0.015
98.7
97.3
99.5
-
0.0048
98.9
99.1
98.9
98.0
-
0.018
98.9
97.6
99.9
100.0
-
0
100.0
100.0
Postwick Hub Scheme - Economic Appraisal Report
5.3.7
Convergence %GAP statistics of the demand-supply model shown in Table 5.5 fall well within the acceptable value of 0.20% of WebTAG, the largest is 0.14%. Table 5.4 shows that user benefits as a percentage of total network costs are between -0.11% and -0.18%. The resultant stability ratios are close to 1 and are lower than the value of 10 recommended in WebTAG thus indicating that there must be a degree of uncertainty in the results. This is a consequence of testing a relatively small transport intervention (a single junction improvement) in the context of a large transport model covering a city, and this is expected.
5.4
Warnings in the TUBA Appraisal
5.4.1
Warnings that were produced by TUBA during the appraisal were used to improve the network and transport model in general. This is described in Appendix C.
5.4.2
All warning messages are consistent with the impacts of the Postwick Hub scheme.
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6. Accident Benefits 6.1.1
Accident benefits were calculated using COBA software (Version 11.15.4.22 which has been updated to work in 2010 prices, discounted to 2010) which uses values in WebTAG 3.4.1. Accident benefits have been calculated for the whole of the modelled highway network.
6.2 6.2.1
Data Sources Data was extracted from the NATS model for the model years of 2015, 2020 and 2030 for input into the COBA assessment. This data included network structure and forecast model flows and was based on post-DIADEM assignments on the Do Minimum and Do Something networks. These assignments used the same Do Minimum input reference matrices (in accordance with WebTAG unit 3.16D “Appraisal in the context of housing development”). The previously prepared Do Minimum COBA models for the BAFB were used as the basis for the Postwick Scheme COBA assessment. Some minor modifications were required to accommodate changes in the Do Minimum networks to account for the revised coding of roundabouts around Postwick junction. Do Something networks were subsequently created from these by including the proposed changes for the Postwick Hub Scheme. As recommended in the COBA manual local accident data was used for the Postwick Junction accident analysis. Norfolk County Council provided accident data for the years between 2002 to 2006 inclusive covering the full Norwich urban area. Further to this, additional accident data was supplied for the area local to Postwick for the period 2007 to 2012 inclusive as indicated in Figure 6.1 below:
Figure 6.1:
Source:
6.2.2
Local Accident Data in the vicinity of Postwick Junction (2007 – 2012)
Postwick Sticks - May 07 to April 12.pdf
COBA is most suitable for fixed demand modelling where the travel demand remains the same for the Do-Minimum and Do-Something scenarios. Therefore, a slightly different process was adopted to accommodate a variable demand modelling approach. This deals with the reflected
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‘different’ traffic growth rates for Do Minimum and Do Something (with impact on vehiclekilometres) between the assessment years of 2015, 2020 and 2030.
6.3
Traffic growth rates
6.3.1
The COBA assessment had to be divided into two separate data files for the Do Minimum and Do Something. The compound annual growth in vehicle-kilometres between the forecast years 2015, 2020 and 2030 is used as the traffic growth rate for the periods between these years.
6.3.2
No further traffic growth is assumed post-2030.
6.4
Network structure and link flows
6.4.1
Link numbers are allocated to the SATURN A-B node references so that A-B and B-A has the same link number with Park and Ride links and zone connector links excluded from the assessment. Links are allocated link types and are given appropriate accident type in the normal way. Observed accident rates are consistent with earlier submissions of the accident analysis.
6.4.2
Link flows are coded in the data files as 2-way AADT flows for the modelled years of 2015, 2020 and 2030. The conversion from average hourly October flows (which is the validation month of the transport model) to AADT uses suitable, calculated factors.
6.4.3
Links that are common to both the Do Minimum and Do Something scenarios are given the same link numbers so that link attributes and observed data can be accurately transferred from the DM to DS data files. New links are given the lowest unused link number available. Link attributes are allocated on a case by case basis for the new links that make up the Postwick Junction proposal.
6.5 6.5.1
6.6
Junction assessment Junctions and links are assessed separately. The accident only junction assessment is only performed on junctions where observed data is available. For new links and junctions in the Do Something network standard accident rates are used for new link and junction combined.
Results Summary
6.6.1
The results in Table 6.1 show that with the Scheme there is a forecast increase in total personal injury accidents (PIAs), but that the forecast casualty severity splits indicate a reduction in fatalities over the period of appraisal when compared with the Do Minimum. The reduction in fatalities is offset by increases in serious and slight casualties, resulting in an overall monetised disbenefit.
6.6.2
The increase in accidents represents £4.19m of disbenefit in 2010 prices, discounted to 2010.
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Table 6.1: Accident assessment summary Do Minim um 60 Year Appraisal Period 94,771
Number of Personal Injury Accidents Casualties
Fatal
2,580
Serious
16,968
Slight
124,194
Accident Costs (£000’s in market prices, discounted to 2010)
8,264,405
Do Som ething 94,906
Number of Personal Injury Accidents Casualties
Fatal
2,578
Serious
16,974
Slight
124,346
Accident Costs (£000’s in market prices, discounted to 2010)
8,268,593
Accident Benefits Number of Personal Injury Accidents Casualties
-134 Fatal
2
Serious
-6
Slight
-152
Accident Savings (£000’s in market prices, discounted to 2010)
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7. Gross Value Added & Development Benefits 7.1
GVA:
7.1.1
The transport scheme will enable the commercial developments at BGBP and LF to take place which will contribute GVA to the local economy as a result of 5000 jobs. Whilst the transport scheme will enable the development to take place, it is not sufficient on its own as of course the commercial development has to be built and the GVA earned. Therefore the GVA should be seen in the context of both the transport scheme and the developments, and the costs of both.
7.1.2
According to the Joint Core Strategy (JCS) evidence base BGBP development will create 3200 jobs, and LF will create 1800 jobs, giving a total of 5000 jobs. It has been assumed that a 10% occupation (500 jobs) could be achieved by 2015, 50% occupation (2500 jobs) by 2020 and full occupation (all 5000 jobs) by 2030; more details on development related details can be found in the Traffic Forecasting Report. The BGBP development proposed is for a mix of B1 and B8. It has thus been assumed that half of the total jobs will be in high productivity activities such as financial services and the rest will be in lower productivity jobs such as warehouse employees. GVA per employee for high productivity jobs is estimated at £45,000 and lower productivity jobs at £29,200 in 2011 prices (A47 Wider Economic Benefits, Mott MacDonald, 2012). This report also indicates that £45,000 per employee is a conservative assumption for high productivity activities such as financial services. The proposed LF development is for a mix of B1, B2 and B8 and their corresponding proportions will be 40%, 30% and 30% respectively. In the absence of more detailed information a conservative assumption that GVA for B2 type employee is similar to B8 type employee is made.
7.1.3
Assuming 320 jobs for the BGBP in each year between 2015 and 2019, 1600 jobs in 2020 and 3200 jobs in 2030 and a linear growth of jobs between these two years, the total GVA for a 30 year appraisal period is £2,701m in 2011 prices (undiscounted). This is £1,210m in 2010 prices discounted to 2010.
7.1.4
Assuming 180 jobs for LF in each year between 2015 and 2019, 900 jobs in 2020 and 1800 jobs in 2030 and a linear growth of jobs between these two years , the total GVA for a 30 year appraisal period is £1,474m in 2011 prices (undiscounted). This is £666m in 2010 prices discounted to 2010.
7.1.5
The total GVA for a 30 year appraisal period for both the BGBP and LF is £1,876m in 2010 prices discounted to 2010.
7.1.6
GVA calculation steps are shown in Table 7.1 below.
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Table 7.1:
GVA calculation steps for BGBP and LF business developments BGBP
LF
Year
Additional jobs with Broadland Gate
GVA estimated (£m in 2011 prices)
GVA £m in 2010 prices discounted to 2010
Additional jobs with Laurel Farm
GVA estimated (£m in 2011 prices)
GVA £m in 2010 prices discounted to 2010
2015
320
12
10
180
6
5
2016
320
12
9
320
11
9
2017
320
12
9
320
11
8
2018
320
12
9
320
11
8
2019
320
12
8
320
11
8
2020
1,600
59
40
900
32
22
2021
1,760
65
43
990
35
23
2022
1,920
71
45
1,080
38
24
2023
2,080
77
47
1,170
42
25
2024
2,240
83
49
1,260
45
26
2025
2,400
89
51
1,350
48
27
2026
2,560
95
52
1,440
51
28
2027
2,720
101
53
1,530
54
29
2028
2,880
107
55
1,620
58
29
2029
3,040
113
56
1,710
61
30
2030
3,200
119
57
1,800
64
31
2031
3,200
119
55
1,800
64
30
2032
3,200
119
53
1,800
64
29
2033
3,200
119
51
1,800
64
28
2034
3,200
119
49
1,800
64
27
2035
3,200
119
48
1,800
64
26
2036
3,200
119
46
1,800
64
25
2037
3,200
119
45
1,800
64
24
2038
3,200
119
43
1,800
64
23
2039
3,200
119
42
1,800
64
22
2040
3,200
119
40
1,800
64
22
2041
3,200
119
39
1,800
64
21
2042
3,200
119
38
1,800
64
20
2043
3,200
119
36
1,800
64
20
2044
3,200
119
35
1,800
64
19
2,701
1,210
1,474
666
GVA over 30 years
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7.1.7
The GVA figure represents the employment benefit at this location. However if the development could not proceed in this location, then it might be expected that it could occur in other locations. That would also mean that access and land would need to be provided which are not currently planned for. A judgement has therefore been made that around only two thirds of the development would occur elsewhere if it were not to proceed at BGBP or LF. The 'additionality' of this is therefore considered to be one third. In addition, the GVA figure has been based on the standard Green Book discount rate of 3.5%. A more cautious approach would apply a commercial discount rate of 6%. If both of these factors are taken into account the additional GVA due to releasing BGBP and LF developments would be £246m and £132m respectively, giving a total of £378m in 2010 prices discounted to 2010.
7.2
Development benefits:
7.2.1
The Postwick Hub Scheme will unlock 30 Ha of office development at BGBP and 17 Ha of mixed development at Laurel Farm. This will focus significant employment close to the Postwick Hub where the proposed transport scheme is designed to accommodate the increased traffic demand and this means that the employment will not be more widely distributed and with consequential larger traffic impacts elsewhere. The latter occurs in the Do Minimum scenario as the development growth is controlled to NTEM and thus the employment is distributed across the local districts with consequential traffic impacts more widely distributed, whereby the proposed scheme will have a less beneficial effect compared with the development being focussed near the Postwick Hub.
7.2.2
According to WebTAG unit 3.16D the combined benefits of the transport intervention and the dependent development would comprise: The transport user benefits of the transport intervention in isolation, and assessed without the dependent development; and The benefits of land use development assuming that the transport intervention is implemented.
7.2.3
The purpose of this section is to calculate the latter while the former is calculated using TUBA and reported on in Section 4 of this document. Benefits of land use development assuming the implementation of the transport intervention are equal to the Planning Gain (PG) arising from the development less the Transport Externality Cost (TEC) and Other Externalities (OE). Here the TEC is produced by the extra congestion for existing transport users, whilst the OE refers to the loss or gain in amenity value of the land compared to its existing use.
7.2.4
The TEC can be positive when the land use development imposes costs on existing users in the absence of a transport scheme improvement, but with an improvement in place it is likely to be negative, especially when the trips are constrained to NTEM. This occurs as the TECs with the specified land use development and the transport improvement are lower than with wider distributed development implied by NTEM without the dependent development. Put another way, with the implementation of the Postwick Hub Scheme the transport externalities are lower with the development close to Postwick than with a wider distribution of development. This outcome is consistent with the WebTAG 3.16D guidance.
7.2.5
PG has been calculated for BGBP assuming that 3ha and 12ha are unlocked in 2015 and 2020 and further 15ha of office development takes place between 2020 and 2030 on non-Previously Developed Land (non-PDL) at the BGBP development site. The current land value of the non-
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PDL is £14,645 in 2010 prices (directly from WebTAG 3.16D spreadsheet for east of England and converted to 2010 prices) while the value of developed land is £1,386,845 (derived by taking an average of 2009 to 2011 January office land values for the eastern region from Valuation Office Agency. 7.2.6
PG has been calculated for LF assuming that 2ha and 7ha are unlocked in 2015 and 2020 and further 8ha of mixed development takes place between 2020 and 2030 on non-PDL at the LF development site. The same land values are used for LF as for BGBP.
7.2.7
Table 7.2 reports the derivation of PG less the OE for the BGBP and LF developments. The total net PG of the development is £36.48m in 2010 prices discounted to 2010.
Table 7.2:
Summary of Planning Gain
Development
Year
Development area (ha)
Value of developed land (£m)
Value of land in existing use (£m)
Net private value (£m)
Net externalit ies (OE) (£m)
Net Planning gain (£m)
BGBP
2015
3
3.5
0.04
3.47
-0.19
3.28
2020
12
11.8
0.12
11.67
-0.74
10.93
2030
15
10.45
0.11
10.34
-0.93
9.41
2015
2
1.91
0.02
1.89
-0.10
1.78
2020
7
6.42
0.07
6.35
-0.41
5.95
2030
8
5.69
0.06
5.63
-0.51
5.12
LF
Total planning gain (£m)
36.48
All monetary values expressed in 2010 prices discounted to 2010
7.2.8
TEC was calculated for a 30 year period from 2015 to 2044 using two transport model runs namely, without the new developments but with the transport intervention and with the new developments and with the transport intervention. Table 7.3 below highlights the calculation of TEC. The negative result for TEC occurs because a transport intervention is being provided to cater for the development traffic, and both scenarios are controlled to NTEM.
Table 7.3:
TEC Summary
Scenario
User Time
Vehicle Operating Costs Fuel
Non_fuel
(£m)
(£m)
(£m)
With the new developments and with the transport intervention
22,574
5,830
6,594
Without the new developments but with the transport intervention
22,591
5,831
6,599
325
49
60
-342
-50
Development only costs TEC TEC total
-65 -457
All monetary values expressed in 2010 prices discounted to 2010
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7.2.9
Table 7.4:
Table 7.4 below summarises the development planning gain benefits of BGBP and LF in millions of pounds in 2010 prices and discounted to 2010. It should be noted that as the TECs are negative and they are subtracted from the planning gain, this results in positive total benefits for the development.
Derivation of BGBP & LF Developments Benefits Benefits (£m)
Planning gain
36.48
Transport external costs
-457.37
Total benefits
493.84
All monetary values expressed in 2010 prices discounted to 2010
7.3
Development Costs
7.3.1
These are estimated by NCC’s partner developer for Broadland Gate to be £88m when converted to a price base of 2010 and discounted to 2010. Development costs for Laurel Farm will be additional to this figure.
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8. Conclusions 8.1.1
The Scheme was assessed in accordance with the approach in WebTAG 3.16D that deals with dependent development. Thus the Scheme was appraised in isolation, without the inclusion of the dependent developments. Results are also presented for the economic impact of the dependent developments based on the benefits of land use development as well as the additional Gross Value Added ("GVA") benefits of enabling 5000 jobs at BGBP and Laurel Farm.
8.1.2
The Scheme is predicted to generate transport disbenefits of £74 million. Accident disbenefits are estimated to be £4 million. Offsetting the disbenefits are the benefits of the land use development unlocked by the Scheme of £494 million and a GVA gain of £378 million to the local economy. The transport scheme costs are £25m and the BGBP development costs are estimated as £88 million by NCC's developer partner (development costs for Laurel Farm will be additional to this figure). All values quoted are in 2010 prices, discounted to 2010.
8.1.3
Whilst the figures show that there will be disbenefits to the existing users of the highway network, the proposed development which would be unlocked by the Scheme would deliver substantial benefits to the local economy which would outweigh the transport disbenefits. In this way, the Scheme will help to deliver the Government's objective that transport infrastructure should support and facilitate economic growth.
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Appendices Appendix A. Annualisation Factors________________________________________________________________ 31 Appendix B. TUBA Setup _______________________________________________________________________ 39 Appendix C. TUBA and COBA Warnings ___________________________________________________________ 42
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Appendix A. Annualisation Factors A.1.
Annualisation Factors
A.1.1.
The following annualisation factors have been used in the economic appraisal:
Table A.1:
Annualisation Factors
Time Period
Annualisation
AM
244
IP
2059
PM
475
OP
2992
Weekend IP
276
Weekend OP
4329
A.1.2.
These annualisation factors have been calculated based on one year counts for a selected number of sites in the Norwich area. Days and time periods that are not specifically part of the transport model (e.g. weekends and bank holidays) have been ‘fitted’ into the modelled time periods as described later in this section.
A.2.
Selection of Count Sites
A.2.1.
The following Automatic Traffic Count (ATC) sites were selected from within the urban area of Norwich for the purpose of producing annualisation factors: Site 11 - A1074 Dereham Road, Norwich Site 34 - C859 Whitefriars, Norwich (2 directions) Site 36 - C852 Cleveland Road, Norwich Site 39 - C850 Prince of Wales Road, Norwich (2 directions) Site 92 - A146, Trowse, Norwich Site 357 - A47, Grapes Hill, Norwich TRADS A47 between A140 and A11, Norwich (2 directions)
A.2.2.
These are the same sites that have been used for annualisation in previous reporting. Figure A.1 shows the location of the ATC sites and Figure A.2 shows the daily profile for each of the ATC sites.
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Figure A.1:
Map showing ATC Sites used for production of Annualisation Factors
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Figure A.2:
October Daily Profile for ATC Sites
October Daily Profile for ATC Sites 3500
3000
2500
2000 Traffic Flow (Vehicles/ Hour) 1500
1000
500
0 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 022:00 23:00 00:00 Hour 11 ‐ dir1
A.3.
34 ‐ dir1
34 ‐ dir2
36 ‐ dir1
39 ‐ dir1
39 ‐ dir2
92 ‐ dir1
357 ‐ dir1
A47b ‐ dir1
A47b ‐ dir2
Calculation of average flows
For Each Site A.3.1.
Each of the selected sites has almost an entire full year of 2006 hourly traffic flow data available. As is commonly the case with traffic data from ATCs, there were small amounts of missing data. For each site, any day that has any missing data has been excluded entirely from the analysis. The following data was calculated for each site: October average traffic flows were found for each hour of the day for weekdays, Saturdays and Sundays. Whole year 2006 average flows were found for each hour of the day for weekdays, Saturdays, Sundays and Bank Holidays.
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For all Sites Combined A.3.2.
To form overall average flows for all the sites combined, a straight average traffic flow was taken for every hour in the day for the 2006 October and 2006 whole year datasets. For sites with counts in two directions, each direction has effectively been treated as an individual site for the averaging process. Figure A.3 shows the October weekday profile calculated from the ATC sites and also displays the inter-peak and off-peak average flows.
Figure A.3:
October Weekday Profile for ATC Sites
October Weekay Hourly Profile vs October Weekday Inter‐Peak and Off‐Peak Average Flows 1600
1400
1200
1000
Traffic Flow (Vehicles/ Hour)
800
600
400
200
0 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 022:00 23:00 00:00 Hour October Weekday Profile
October Weekday Inter‐Peak
October Weekday Off‐Peak
A.4.
Designation of Weekday Hours
A.4.1.
The following assumptions have been applied in the derivation of weekday annualisation factors: AM period (800-900) benefits have been derived from the AM peak hour model (800-900) PM period (1600-1800) benefits have been derived from the PM peak hour model (17001800) Inter Peak period (700-800, 900-1600, 1800-1900) benefits have been derived from the inter peak model (average hour 1000-1600) Off Peak period (1000-1600) benefits have been derived from the off peak model (average hour 1900-700)
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A.5.
Designation of Saturday, Sunday and Bank Holiday hours as Interpeak or Off-peak
A.5.1.
As there is no weekend assignment model, it was necessary to designate weekend hours as either weekend inter-peak or weekend off-peak in order to produce a full annualisation. 2006 October weekday average flows for the inter-peak average hour and the off-peak average hour were calculated and compared with October average Saturday hourly traffic flows, see Figure A.4 below.
Figure A.4:
October Saturday Profile for ATC Sites
October Saturday Hourly Profile vs October Weekday Inter‐Peak and Off‐Peak Average Flows 1200
1000
800
Traffic Flow (Vehicles/ Hour)
600
400
200
0 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 022:00 23:00 00:00 Hour October Saturday Profile
October Weekday Inter‐Peak
October Weekday Off‐Peak
A.5.2.
It was found that the October inter-peak average hour was 941vehicles/hour and the October offpeak average hour was 255 vehicles/hour.
A.5.3.
To produce a robust annualisation, it was considered that all Saturday hourly traffic flows found to be greater than the October weekday inter-peak average hour should be designated as weekend inter-peak and all other hours should be designated as weekend off-peak.
A.5.4.
The designation of Saturday hours as inter-peak or as off-peak is shown in and Table A.2.
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Table A.2:
Designation of October Saturday 07:00 - 19:00 Hours
Hour
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
Flow
334
624
823
948
1023
1075
1060
989
920
920
922
774
Designation
OP
OP
OP
IP
IP
IP
IP
IP
OP
OP
OP
OP
A.5.5.
All Sunday and Bank Holiday hourly flows were designated as weekend off-peak.
A.6.
Calculation of Annualisation Factors
A.6.1.
The annualisation factors were calculated by dividing the total flow in 2006 by the average October 2006 hourly flow for each time period. The annualisation factors are shown below in Table A.3.
Table A.3:
Calculation of Annualisation Factors
Flow Description
Traffic Flow (Vehicles)
Average October AM Peak Hour
1304
Total AM Period for Year
317666
AM Annualisation Factor
244
Average October PM Peak Hour
1335
Total PM Period for Year
633489
PM Annualisation Factor
475
Average October Inter-peak Hour
964
Total Inter-peak Period for Year
2150441
IP Annualisation Factor
2059
Average October Off-peak Hour
245
Total Off-peak Period for Year
733797
OP Annualisation Factor
2992
Average October Inter-peak Hour
964
Total Weekend IP Period for Year
260008
IP Weekend Annualisation Factor
270
Average October Off-peak Hour
245
Total Weekend OP Period for Year
1051268
OP Weekend Annualisation Factor
4287
A.7.
Journey Purpose Splits for Weekend Time Periods
A.7.1.
The composition of non-freight car/ personal LGV was adjusted for the weekend inter-peak and off-peak time periods so that each journey purpose represented the following proportion of total non-freight demand: Commute: 9.1% Employers Business: 1.7% Other 89.2%
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A.7.2.
In a similar way the weekend inter-peak and off-peak demand was adjusted for public transport so that each purpose represented the following proportion of total public transport demand: Commute: 12.4% Employers Business: 1.0% Other 86.6%
A.7.3.
The journey purpose proportions were obtained from WebTAG 3.5.6 Table 8: Proportion of Trips Made in Work and Non-Work Time.
A.8.
Weekend Adjustment for Freight
A.8.1.
Annualisation factors derived from total ATC traffic flows, as described above, do not provide an accurate representation of freight demand, particularly due to differences between traffic composition in weekend hours and during weekday inter-peak and off-peak average hours.
A.8.2.
The 2006 ATCs used to derive anualisation factors were not classified. More recent ATC data included classification by vehicle type has been used to calculate freight adjustment factors. This data was not used to derive overall annualisation factors as it does not represent the base year of 2006. Figure A.5 below shows the locations of the ATC sites.
Figure A.5:
Map showing ATC Sites used for production of Freight Annualisation Variation Factors
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A.8.3.
Classified data was available for the ATC sites for 2008 and 2010. Although the data is from years that are different from the 2006 base year, it was considered that for the purpose of comparing freight flows at the weekend and during a weekday, the data would be appropriate.
A.8.4.
Using the classified traffic data, freight weekend demand adjustment factors were calculated by comparing the proportion of traffic that is freight during the average weekday inter-peak and offpeak with the designated inter-peak and off-peak weekend periods. Table A.4 shows the calculated freight weekend demand adjustment factors.
Table A.4:
Freight Weekend Demand Adjustment Factors
Time Period
LGV
OGV
Weekend IP
0.35
0.29
Weekend OP
0.52
0.45
A.8.5.
The freight demand adjustment factors are affected through the matrix factoring process in the TUBA setup.
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Appendix B. TUBA Setup B.1.
Demand
B.1.1.
The DIADEM variable demand model provides TUBA with input demand matrices for highway and public transport modes.
B.1.2.
Highway demand is provided as Passenger Car Units (PCUs) and the public transport demand is provided as passengers. Table B.1 and Table B.2 show the input demand segmentation.
Table B.1:
Highway Demand Segmentation
User Class
Vehicle Type
Purpose
1
Car/LGV
Home Based Commute
2
Car
Home Based Employers Business Non-Home Based Employers Business
3
Car/LGV
Home Based Other Non-Home Based Other
4
LGV
Employers Business
5
OGV
Employers Business
Table B.2:
Public Transport Demand Segmentation
User Class
Purpose
1
Home Based Commute
2
Home Based Employers Business Non-Home Based Employers Business
3
Home Based Other Non-Home Based Other
B.2.
Skims
B.2.1.
The DIADEM demand model, in combination with the highway and public transport assignment models produces skims of time, distance and cost as shown in Table B.3 and Table B.4 below.
Table B.3:
Summary of Highway Skims
Highway Skim
Assignment Unit
TUBA Unit
Vehicle Trips
PCUs/Hour
Vehicles/Hour
Distance
Metres
Kilometres
Time
Seconds
Hours
Car Parking (Local Authority)
Pence
Pence
Car Parking (Private)
Pence
Pence
Table B.4:
Summary of Public Transport Skims
Highway Skim
Assignment Unit
TUBA Unit
Passenger Trips
Passengers/Hour
Passengers/Hour
Time
Seconds
Hours
Fare
Pounds
Pence
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B.3.
Current, Modelled and Appraisal Years
B.3.1.
TUBA requires a minimum of two years to be modelled and interpolates/extrapolates benefits for other years over the 60 year appraisal period. For each modelled year, demand and skim matrices for do-minimum and do-something scenarios were input to TUBA. The following years have been included in the scheme file: Current Year – 2013 Modelled Years – 2015, 2020, 2030 Appraisal Period – 2015 – 2074 (60 years)
B.4.
User Classes
B.4.1.
In order to split each TUBA Purpose as defined in the economics file into each possible TUBA Vehicle Type, the following user class structure, as shown in Table B.5, was devised.
Table B.5:
TUBA User Classes
TUBA User Class
TUBA Vehicle Type
TUBA Purpose
TUBA Person Type
1
Car
Home Based Commute
All*
2
LGV (personal)
Home Based Commute
All*
3
Car
Home Based Employers Business Non-Home Based Employers Business
All*
4
Car
Home Based Other Non-Home Based Other
All*
5
LGV (personal)
Home Based Other Non-Home Based Other
All*
6
LGV (freight)
Non-Home Based Employers Business
All*
7
OGV1
Non-Home Based Employers Business
All*
8
OGV2
Non-Home Based Employers Business
All*
12
Public Transport
Home Based Commute
Passenger
13
Public Transport
Home Based Employers Business Non-Home Based Employers Business
Passenger
14
Public Transport
Home Based Other Non-Home Based Other
Passenger
*All TUBA person type split by TUBA into drivers and passengers using default proportions from the economics file
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B.5.
Demand and Skim Matrix Factors
Demand Factors B.5.1.
The combined car/ personal LGV user classes as supplied by the DIADEM demand model were split into the separate car and personal LGV user classes as used in TUBA using factors derived from the base year matrix build.
B.5.2.
The following factors, shown in Table B.6, were used top convert the OGV (all) user class in PCUs supplied by the DIADEM demand model to the OGV1 and OGV2 user classes in vehicles as used by TUBA.
Table B.6:
Vehicular Conversion of OGV User Class
Factor
OGV1
OGV2
PCU to vehicle factor
0.448
0.448
OGV1/ OGV2 Split
63%
37%
OGV (all) PCU to Vehicle Factor
0.283
0.166
B.6.
Skim Factors
Unit Conversion B.6.1. Table B.7:
Table B.7 and Table B.8 show the unit conversion factors used in TUBA. Unit Conversion of Highway Skims
Highway Skim
Assignment Unit
TUBA Unit
Distance
Metres
Km
Time
Seconds
Hours
0.00028
Car Parking (Local Authority)
Pence
Pence
1
Car Parking (Private)
Pence
Pence
1
Table B.8:
Unit Conversion Factor 0.001
Unit Conversion of Public Transport Skims
Highway Skim
Assignment Unit
TUBA Unit
TUBA Unit
Time
Seconds
Hours
0.00028
Fare
Pounds
Pence
100
Split Public/ Private Parking Charges B.6.2.
Parking charges have been split as 80% private sector, 20% public sector.
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Appendix C. TUBA and COBA Warnings C.1.
Summary of TUBA Warnings
C.1.1.
Table C.1 below provides a summary of the warnings produced by TUBA.
Table C.1:
Summary of TUBA Warnings
Warning Type
Number of warnings (Serious Warnings)
Ratio of DM to DS Journey Time too Low
999 (32)
Ratio of DM to DS Journey Time too High
8,342 (1,984)
Ratio of DM to DS Distance too Low
6,643 (1,920)
Ratio of DM to DS Distance too High
11,954
DM Speed too Low
241,069
DS Speed too Low
236,642
C.2.
Investigation of serious TUBA warnings
Ratio of DM to DS Journey Time too Low C.2.1.
These warnings occur where there is a significant rise in journey time from Do Minimum to Do Something scenarios. The vast majority of the serious warnings relate to travel involving a trip end in Sector 1, which are as expected due to trips switching from normal links to Park & Ride links.
Ratio of DM to DS Journey Time too High C.2.2.
These warnings occur where there is a significant decrease in journey time from Do Minimum to Do Something scenarios. Again, the vast majority of the serious warnings relate to travel involving a trip end in Sector 1, which are as expected due to trips switching from Park & Ride links to normal links.
Ratio of DM to DS Distance too Low C.2.3.
These warnings occur where there is a significant rise in trip distance from Do Minimum to Do Something scenarios. Almost all of these serious warnings have a trip end in Sector 1 and it is considered that these warnings are caused by trips switching from Park & Ride links to normal links.
Ratio of DM to DS Distance too High C.2.4.
These warnings occur where there is a significant decrease in journey distance from Do Minimum to Do Something scenarios. The majority of the serious warnings relate to travel involving a trip end in Sector 1, which are as expected due to trips switching from normal links to Park & Ride links.
DM Speed too Low & DS Speed too Low C.2.5.
These warnings occur where speeds are low. The vast majority of these warnings have a trip end in Sector 1. Investigation of these warnings has found that they relate to travel on Park and Ride
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and are acceptable. In the modelling of Park and Ride, for the bus leg of the journey the bus journey time is included in the time skims but there is no distance included in the distance skims.
C.3.
COBA Warning Messages
C.3.1.
The COBA results file contained instances of the following warning messages. An explanation of the warning is given in the sub-bullet point.
Additional header or delimiter (9999) lines have been inserted by the program. C.3.2.
Additional header information is inserted by the COBA program to ensure the successful running of the model.
Some link lengths were greater than 10 km (classes 1-6 and 9-12) or 3 km (classes 7-8). C.3.3.
These long links relate to the external links at the periphery if the model.
Link overcapacity was detected. C.3.4.
Refers to a level of link flow that is beyond COBA defaults for a given link type. These have been checked and are acceptable.
There was link or node overcapacity in the do-minimum/do-something scheme. C.3.5.
As above.
Respecifications or reclassifications caused overcapacity junctions or roads to become undercapacity C.3.6.
These have been checked and are acceptable. Explicit link flows are given for each forecast years, 2020 and 2030, rather than applying forecast growth rates.
Entry link flows have been changed C.3.7.
As above.
Accident rates were given which exceeded the warning limit. C.3.8.
Accident rates for some links in the period 2002 – 2006 exceed COBA defaults for a given link type. These have been checked and are acceptable.
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