Approach to Sustainability
Developing the Baseline for Emissions Modelling
7 August 2019
2
Purpose and Process
Purpose
• To confirm the recommended approach to emissions modelling for the SGA
programme, including defining the Baseline Scenario
Process
• SGA consideration of issues and options
• Liaison with AT and NZTA sustainability teams (6/8/19)
• Recommended Approach
3
General Approach to Emissions Modelling
• Use the VEPM model to estimate emissions rates (kg/VKT by vehicle speed) for current and future
years (noting rates are forecast to reduce based on current and assumed future vehicle fleet
changes)
• Apply VEPM rates to transportation models (VKT by link speed) to estimate emissions per peak
period, aggregated to average day
• Model emissions generation only, not dispersion
• Assess the impact of the transport intervention by comparing Scenarios:
• Existing: Current situation for reference (2016 or 2018 model)
• Baseline: A future without the recommended intervention
• Option: A future the proposed transport intervention
• Assess future via short, medium and long term forecasts: 2028, 2038, 2048 forecast years
• Sensitivity test long-term results with shorter-term rates, to separately identify the impact of the
assumed future fleet changes
4
Required Inputs to Transport Model Scenarios
• Key inputs to the scenarios are:
• Land use/demographic inputs for each forecast year
• Future transport system assumptions
• Economic/policy assumptions (e.g. fuel price, public transport fares, Travel Demand Management (TDM)
policy impacts on travel etc)
• Impact of the Transport Interventions:
• Directly influences travel choices and patterns (e.g. VKT)
• Directly influences network performance (e.g. speed)
• Directly or indirectly can influence land use patterns (through enabling capacity or system performance)
• Unlikely to influence economic/policy inputs at SGA project or programme level
5
Issues and Context
• The greenfield
growth has been signaled in the AUP, and the form defined in some locations through
Structure Plans
• Decisions on releasing growth sit with
Auckland Council, informed by transportation needs or impacts
• SGAs role to
protect corridors that allow
future implementation of the identified preferred transport system
• SGA approach therefore to get
best outcomes for the planned growth, not to assess the value of the growth
itself
• The transport networks are being design for long-term with
both planned greenfield and brownfield
growth assumed
• Land use and transport planning is being progressed in an integrated way for the desired, integrated
outcomes (i.e. non-desired networks or land use are not being actively designed as a ‘counter-factual’)
• ‘Baselines’ have been defined for SGA as including full planned growth for:
• economic evaluation
• The ‘existing environment’ definition for option assessment and AEE
6
Measures for Scenario Comparison
Regional or area totals
✓More useful to understand net impact on emissions
➢
Both measures
❖not useful to compare between options with different levels of
have strengths
and weaknesses
growth
➢
Use both as
appropriate
Per-Capita Values
✓Can compare between scenarios with different levels of growth
❖sub-area comparators can be biased by location in regard to
local vs through traffic
7
Options for Baseline Transport inputs
The Option scenario will include the recommended transport system, however there are options
for treatment of the Baseline comparator:
1.
Use a
future Do Minimum network for the Baseline. As per BCR and AEE assessments,
this would typical comprise the existing network plus only committed projects
2.
Use an
Alternative future network. This could be developed around ‘previous’ policy
settings/standards or ‘traditional’ network (e.g. dominated by roads for personal car travel)
3.
Use the
existing scenario (e.g. a 2016 model (or 2018 if available)
8
Assessment of Baseline Transport Options
Option 1 (Do Minimum)
✓ Easy to define
✓ Spatially comparable to the fully-developed ‘Recommended Option’ scenario
➢
All options have strengths
✓ Consistent with EEM and AEE approaches, but
and weaknesses
❖ May not fully demonstrate the value of the recommended networks, relative to ‘traditional’ approaches
➢
Option 2 not preferred as
❖ Somewhat artificial/unrealistic situation with full growth development on a Do Minimum network
requires additional analysis
for limited value
Option 2 (Alternative Network)
➢
Recommend use mainly
Option 1 but with Option 3
✓ Could better demonstrate the value of the recommended network, relative to a ‘traditional’ approach
used for reference
✓ Spatially comparable to the fully-developed ‘Recommended Option’ scenario, but:
❖ Hard to define and requires additional design and assessment of an alternative network
❖ Arbitrary and contrary to current objectives, policies, expectations, standards
❖ Outcomes will be sensitive to the design of the alternative network
Option 3: Existing situation
✓ Easy to measure, high level of certainty and not sensitive to assumptions :
❖ Not comparable with future vehicle fleet (although this could be addressed by using future fleet assumptions on current-day transport network)
❖ Existing developed areas may not be spatially comparable with growth areas
9
Options for Land Use inputs to Scenarios
1. Use a
common regional population total for both Baseline and Option
scenarios that includes all planned growth. Sensitivity testing of alternative
location/density can be included
2. Use
variable land use inputs with full planned growth for the Option scenario
but constrained growth for the Baseline
10
Assessment of Baseline Land Use Options
Option 1 (Common Land Use)
➢
Recommend Option 1
• Can directly compare outcomes
(Common Land Use) for the
• Evaluates transport intervention, not growth
Modelling Baseline
• Evaluation is contained within Auckland Region
➢
Sensitivity test alternative
land use scenarios that
• Is consistent with EEM and AEE approaches, but
retain same regional growth
• Assumes growth is immutable, which may not reflect enabling/influencing role of transport on
but alternative forms of
growth
employment location and
housing density
Option 2 (Variable Land Use Inputs)
• Makes direct comparison of outputs very difficult (emissions would be compared per capita rather
than in absolute terms
• Assumes any constrained growth occurs ‘elsewhere’ in NZ or globally, beyond scope of the
evaluation
• Could effectively include impacts of growth, rather than the transport intervention
• Ability to predict the required alternative and constrained baseline land use growth is weak
11
Suggested Baseline
• Use
total emissions as key indicator to compare future scenarios but
• also use
per-capita values to benchmark against current day network and other areas (controlling for changes in fleet composition)
•
Sensitivity test with and without changes related to
future vehicle fleet assumptions
• Assume
Common land use for Baseline and Option scenarios, comprising:
• Full development of Greenfield areas with total yield as per Council forecasts
• Regional growth as per agreed Auckland Forecasting Centre forecasts
•
Sensitivity test with revised spatial allocations, retaining regional total:
• Centralised employment (reduced in growth areas)
• Dispersed density (rather than Structure Plan focus around stations)
• Use a ‘
Do Minimum’ transport network as the Baseline Network, comprising:
• existing network
• Plus committed projects in growth area
• Plus ‘ATAP3’ assumptions outside growth areas
• Assumed local and collector roads plus reduced speeds on rural roads in greenfield growth areas
• Use common ‘ATAP3’ economic and policy inputs to models
