Tools for Representing and Appraising the Distributional
Impacts of Policies
Example: Streetspace Allocation
Peter Jones & James Paskins
Centre for Transport Studies, UCL
Leeds, 21st May 2007
Current Situation• Authorities encouraged to measure distributional
impacts of strategies and schemes – but little guidance
• Main advice relates to taking into account effects of income differences (e.g. equivalence scales, distributional weights)
• Recent legislation in UK to ensure no discrimination, in terms of disability, age, ethnicity, gender – strengthens case for examining distributional impacts
Distributional Dimensions
• WHO: Social group distribution (‘vertical equity’):– Directly affected (e.g. children)– Indirectly affected (e.g. parents)
• WHERE: Spatial distribution (‘horizontal equity’):– Design area– Wider impact area
• WHEN: Temporal distribution:– Time period– Generational/cohort differences
Requirements of Tools
• Aid identification of relevant social groups, plus spatial and temporal impact areas
• Identify relevant categories and measures of impacts
• Provide basis for assessing gainers and losers, and severity/significance of change
• Consider possibility of integration into current appraisal methodologies
Types of Tool Development
1. Congestion charging: Bristol, Edinburgh (PROGRESS), WebTag guidance
2. Accessibility Planning: Barnsley Dearne, South Yorkshire
3. Streetspace reallocation: Bloxwich, West Midlands
Streetspace Reallocation
• Increasing emphasis on redesigning high streets:– Encourage more sustainable modes– Regenerate high streets & increase liveability
• Given space/capacity limitations, more for one group often means less for others
• Need a method of assessing design needs and gainers/losers under different options
Option Generation & Appraisal
Winners and Losers Net Benefits
Determine Street Type
Determine Street User Groups and Activities
Determine Required Street Elements
Determine Desired Numbers/Space
Determine Net Nos./ Space Requirements
Appraise Against Current Conditions
Generate Streetspace Design Options:
•Types/Numbers Street Design Elements• Location of Street Design Elements
Winners and Losers Net Benefits
Determine Street Type
Determine Street User Groups and Activities
Determine Required Street Elements
Determine Desired Numbers/Space
Determine Net Nos./ Space Requirements
Appraise Against Current Conditions
Generate Streetspace Design Options:
•Types/Numbers Street Design Elements• Location of Street Design Elements
Determine Street Type
Source:‘Link and Place - A Guide to Street Planning and Design’
I-B I-C I-D I-EI-A
II-A
III-A
II-B II-C
III-B
II-D II-E
III-C III-D III-E
V-A
IV-B IV-C IV-D IV-E
V-B V-C V-D V-EL
oca
l
Ne
igh
bo
ur
ho
od
Dis
tric
t
City
Na
tion
al
Neighbourhood
Local
District
City
National
IV-A
Arterial streets
Non-arterial streets
Place status (A, B, C, D and E)
Lin
k s
tatu
s (
I, I
I, I
II,
IV a
nd
V)
Link/Place classification matrix
Select Street User Groups/Activities
Street type
User group … I - E … III - B
Retail … V - E
Pedestrians Pedestrians who have mobility difficulties Those using the street to socialise/relax Cyclists Bus users visiting the street Those travelling to other destinations Car users (non-disabled) visiting the streett Disabled car users visiting the street …
Requirement for Street Elements
Crossing places
Traffic island
Street seating
Cycle stands
Cycle lane
Bus lane
Bus bays
Running lanes
Parking bays
Disabled parking bays
Loading bays
Pedestrians ● ●
Pedestrians who have mobility difficulties ● ●
Those using the street to socialise/relax ●
Cyclists ● ● ● ●
Bus users visiting the street ● ● ● ●
Those travelling to other destinations - all modes ●
Car users (non-disabled) visiting the street ● ● ●
Disabled car users visiting the street ● ● ● ● ●
Shopkeepers ● ●
Minimum Design Requirements
Existing Spaces
Design Spaces
Parking Bays 10 12
Loading Bays 10 14
Disabled Bays 2 4
Bus Stops 4 4
Crossings 3 3
Blocks – Colour and Size
• Use colour to denote different types of space usage
• Some based on current street colour categories; e.g. blue = disabled parking (blue badge)
• Size represents to scale space required to accommodate feature
Differences in Provision by Option
Plan A Plan B Plan C
General Parking Yellow 4 4 10
Disabled Parking Blue 2 8 2
Loading Brown 2 2 2
Bus Stop Orange 1 1 1
Appraisal Spreadsheet
• Compares the impacts of various street designs on different user groups
• Inputs include desired and actual levels of provision for each street element
• Output is a comparison of the impacts for the various user groups
• Following example replaces 6 parking bays with a bus stop
User Impact Matrix
• Matrix indicates relevance of different street features to different user groups
• Impacts are only positive (1) or negative (-1);
the matrix does not include any weighting
Provision and Impacts
The screenshot shows the spreadsheet being used to show the impacts of replacing 6 parking spaces with a bus stop
Current plan elements are entered here
Proposed plan elements are entered here
Provision and Impacts
The impact matrix is used to calculate the impacts from the current provision and for the proposed plan
Spreadsheet Output
• Comparison shows there will be a positive impact for bus users and negative impacts for car users (including disabled car users)
• BUT this comparison did not take account of: – the relative importance of the user groups
or – the ideal or maximum numbers of elements
Adding User Group Weights
• The weightings in the matrix could be altered (e.g.) to favour plan options that:– Prioritise bus users– Prioritise disabled car users– Discourage car use by other groups
User group Original weighting Revised weighting
Bus passengers 1 5
Disabled car users
1 2
Car users 1 0.5
Revised Impact Matrix
• The weightings are then fed into the impact matrix……….
Bus user weighting
Car user weighting
Disabled user weighting
Street Element Weighting
• There may be an upper limit, or ideal number of a particular element
• The spreadsheet currently allows a maximum provision point to be set; after this point, increasing provision does not increase the benefit for any group
• It is possible to include other relationships, for instance diminishing returns
Setting a Cut-Off Point
Parking spaces
Uti
lity Adding extra
spaces does not increase the benefit
• In this example, the maximum number of parking spaces has been set at 6
Spreadsheet with Weightings
• The revised impact matrix now includes the following:
A. User Group Priorities:– Priority for bus users– Priority for disabled drivers– De-prioritising car users
• Cut-off point for parking spaces:– After 6 have been provided there is no benefit
from additional provision
Conclusions
• Spreadsheet currently under development, as an aid to option appraisal/selection – and to more targeted option generation
• Encourages more explicit treatment of objectives, priorities and needs
• More work required on inputs
• BUT, as yet, does not take into account location of design elements along a street
Contact Details
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