Generating Scheme Options and Exploring Distributional Impacts

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Generating Scheme OptionsandExploring
Distributional Impacts

• Final workshop of the DISTILLATE programme
• Great Minster House, London
• Tuesday 22nd January 2008
• James Paskins
• UCL

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Objectives

• To develop option generation methods
• To enhance the range, innovation and quality of
  options
• For strategies and schemes

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Four Option Generation Products
Strategies Schemes
Inside the box Packages of urban measures KonSULT Streetspace main road redesign (Bloxwich)
Outside the box Accessibility Planning options (Barnsley Dearne) Community space design (Blackpool)
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Facilitating Community Space Design Using
Participatory GIS to generate options
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Problem Features What do people want to see
changed?
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Future Changes - What do people want to see
happen?
Business-as-usual
minor infrastructure improvements
Pedestrian priority
Major changes to promote community use of the
space
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Out-of-the-Box Options

• Participants were encouraged to consider and
  justify their suggestions
• They were guided through this using flow chart
• This helped to identify alternative
  out-of-the-box solutions

For example What would you change? Improve the
car park How? More disabled bays and better
signage Why do you want this change? Improve
safety of users How else could you make the area
feel safer? Stop the kids hanging around How
would you do to achieve this? Put in facilities
for kids

• So a solution to a transport issue might be
  better play facilities

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Designing Streetspace Options

• Urban street design often causes major
  controversy difficult to gain public support
• Conventionally engineers develop a preferred
  solution, which goes to consultation
• Little attention paid to options
• Which street design elements are included?
• How many and when?
• Where are they located?

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The Tools Blocks Bytes

• For use in more complex streets, where have many
  competing street user groups
• Two complementary techniques
• Physical design exercise with local communities
  scale plans, blocks, acetates
• Conversion to electronic, GIS format, for use in
  larger public meetings and for developing
  engineering drawings

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Tool 1 - Blocks

• By using blocks to scale, and detailed maps of
  the high street
• Users are made aware of many of the component
  options for allocating street space
• They then generate their own options, by
  combining blocks in different ways and locations
• Maps to scale allow users to work within the
  constraints that the engineers, face without
  having to have a detailed knowledge.

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Example of Loading Bay Block
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Blocks Colour and Size
Feature Colour
Vehicle Lane Grey
Bus Lane Red
Cycle Lane Green
General Parking Yellow
Disabled Parking Blue
Loading Brown
Bus Stop Orange
Traffic Island Cyan
Signal Crossing/ Zebra Approach Magenta

• Use of colour to denote different types of space
  usage
• Some of these based on current street colour
  categories, e.g. blue denotes disabled parking
  (blue badge)

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Street Element Design Options
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Tool 2 - Bytes

• Based on a development of LineMap, a GIS based
  tool developed by Buchanan Computing to plot road
  markings
• The software plots all road markings from Traffic
  Signs Regulations and General Directions (TSRGD)
  2002
• Now converts to/from the block format, and can be
  edited on screen

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Conversion Blocks -gt Lines
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Scheme Comparison
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Display Bus on Bloxwich High Street
The display includes the full plan, information
about red routes and a description of the
planning process.
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Conclusions

• Using scale blocks and maps makes the design
  process as simple as possible to understand, and
  highlights opportunities and constraints
• LineMap provides a bridge between outline design
  and professional drawings suitable for use in
  larger public meetings for scheme editing
• Enables councils to regain confidence of local
  people and plan with a wider understanding of the
  needs of an area.
• Allows members of the public to participate in
  street design and encourages innovative solutions
• High level of public support for resulting scheme
• Council very pleased with outcome removes
  normal confrontational approach
• Walsall has purchased copies of both tools, and
  plans to repeat in other parts of the Borough,
  where face major opposition

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Identifying Distributional Impacts
Inputs
Impacts
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Benefits Matrix

• The impact calculations rely on a matrix that
  specifies whether a design element has a positive
  or negative impact for a particular user group

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Fine Tuning the Comparisons

• Weightings can be applied to
• User groups
• Street design elements
• Individual user group/element pairs
• Adjusting the weights allows the comparison to
  reflect the relative importance of particular
  user groups or street design elements
• Values in the matrix can be adjusted to show the
  particular importance of a design element to a
  particular group for instance, disabled parking
  bays for disabled drivers

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Using Alternative Relationships

• The default relationship between street design
  element and impact is linear
• Different relationships, such as maximum
  provision and diminishing returns, can be applied
  to each street design element

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A B C D E
Comparison area
Existing provision
Group 1 scheme
Group 2 scheme
Final scheme
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Weighted versus Unweighted

• The following sheet shows the results of two
  types of scheme comparison
• Unweighted comparison
• Comparison with the following weights and
  relationships

• Diminishing impact of increasing parking
  provision
• 10 per space for reduction for increases above
  20 spaces after 20 for all user groups
• Priority for bus users
• A weight of 2 given to bus stops for all user
  groups
• Representing the decreased usefulness of standard
  parking bays for disabled car users
• A weight of 0.5 given to standard parking spaces
  for disabled car users

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Comparison of Impacts
Street User Group Existing provision (B) Group 1 scheme (C) Group2 scheme (D) Final scheme (E)
Pedestrians N/A Comparison Plan 0 0 0
Pedestrians who have mobility difficulties N/A Comparison Plan 0 0 0
Those using the street to socialise/relax N/A Comparison Plan 0 0 0
Cyclists N/A Comparison Plan 0 0 0
Bus users visiting the street N/A Comparison Plan -4 -2 0
Those using the street as a link N/A Comparison Plan 0 0 0
Car users (non-disabled) visiting the street N/A Comparison Plan 11.94 10.86 9.22
Disabled car users visiting the street N/A Comparison Plan 2.97 7.43 0.61
Shopkeepers N/A Comparison Plan 1 1 1
Unweighted Total 34 32 19
Total 11.91 17.29 10.83
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Spreadsheet Conclusions

• The spreadsheet provides an objective and
  flexible framework for helping to compare
  different plan options
• Careful thought is required about the weightings
  and relationships that are chosen
• Policy priorities
• Usage patterns
• The spreadsheet fits in well with the option
  generation techniques that have been developed as
  part of DISTILLATE

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Questions?

• Contact
• Professor Peter Jones
• Centre for Transport Studies
• peter.jones_at_ucl.ac.uk
• Tel [phone]
• www.distillate.ac.uk