Transcript The Impact of Fast Route Geometry in London

On the impact of fast route geometry in
London with some strategic applications
Les Mayhew
Cass Business School
International Geographical Union (IGU) conference
Leeds University, 2013
[email protected]
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Geographical theory and urban
analogues
Classical geographical theory
•Central place theory, hierarchies,
economic efficiency, spatial equilibrium,
accessibility
•Optimum location of the firm, market
areas, competition
•Minimisation of production,
distribution, and environmental costs
•Travelling salesman involving delivery
systems, problems involving
minimisation of travel costs
•Network assignment problems, queuing
theory, modal split, shortest paths
Urban analogues
• Retail centres, health care facility location,
administrative centres
• Airport and railway hubs, out of town retail
centres, river crossings
• Assembly systems, warehousing, delivery
systems (e.g. parcels, food)
• Emergency response systems (police, fire,
ambulance)
• Road charging, traffic management, air
quality
• Strategic planning and public policy
(housing, employment and public
transport)
• Green Belt and parks
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Challenges and tools
• Spatial representation and mapping of urban areas –
concentric, multi-centred, coastal, estuarine
• Urban metrics – not undifferentiated planes but a
more complex geometry (e.g. networks, non-Euclidean,
or other geometry)
• How to integrate spatial decision making with
economic aspects viz. generalised costs of travel, costbenefit analysis
• Spatial and mathematical tools which should be simple
to understand, general and abstract from reality i.e.
based universal principles and transparent assumptions
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Structure
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


Urban spatial metrics and key spatial concepts
– a refresher
Introduction to properties of orbital radial
metrics
Overview of applications including congestion
charging, airport location, river crossings and
urban structure
Concluding remarks
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Travel within urban areas:
Alternative metrics
Euclidean travel in
undifferentiated plane
Time-Cost minimisation (nonEuclidean)
Cartesian (‘Manhattan’ metric)
Double radial metric
Orbital – radial metric
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Basic geometric concepts
Areas and isochrones
t
Isochrones and shortest paths
Route catchments
Market areas
Regular tessellated market areas
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Fundamental time surfaces
Source: Hyman and Mayhew 1984
Time surfaces are 3-D
representations on which
distance equates to travel
time. Distance is
measured in minutes or
hours and areas in square
minutes or hours.
Patterns on time surfaces
such as tessellated
market areas can be
transformed to the urban
plane and their
properties studied.
Fundamental surfaces
include the cylinder,
cone, sphere and plane
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Tessellated urban planes based on
different underlying time surfaces
These tessellations are
generated from 3-D time
surfaces and show the
intricacies of tessellated
patterns achievable. In
these cases average travel
speeds increase with
distance from the city
centre. Every market area
however has the same
travel time radius, the sizes
of which are a function of
local travel speeds and
road configuration.
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Example: 10-minute isochrones around A&E
centres
Map based on access to local
A&E centres in London. Around
each centre is drawn a 10-minute
isochrone. The isochrones do not
tessellate as in the time surfaces
but in the real world we can
always expect imperfection. With
GPS systems and data extractable
from systems such as Google
Map the data exist to calibrate
such maps with considerable
accuracy.
Local movement constricted by local road configuration and traffic density.
Movement in outer areas less constricted and so fewer centres are needed
0 . 33
This map is based on average speeds increasing according to V   r
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Route catchments and isochrones
Concentric city with radial and orbital
movement
C
quickest paths
isochrones
route
catchment
D
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Urban orbital-radial metric in concentric
cities
Travel time via centre
t  (r1  r 2) / V A
Travel time via ring
t  ( R  r 1) / V A  ( R  r 2 ) / V A  R  / V B
R = ring radius
VA= radial speed
R1= fixed trip end
R2= variable trip end
=angle between R1 and R2
VB=orbital speed
k=VA/VB
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Test of orbital efficiency
destination
destination
Orbital and radial route catchments based on an exterior destination
north of the city centre destination located outside the orbital
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Congestion charging
• Introduced in London in
2003
• It covers an area of about
3km in radius
• It aims to reduce congestion
and raise funds for London's
transport system
• It costs £10 a day between
7:00 and 18:00 on weekdays
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Spatial impact of central congestion charging on
route catchments in a 3-ringed city
Maps demonstrating
the power of
congestion charging to
re-direct traffic and the
need to measure
effects over a wide
area. Route catchments
are based on four
routing options
consisting of three
orbital routes and radial
travel
Route catchment maps for two fixed locations: (A) At 7.5 kms, no charge; (B) At 18.5
kms, no charge; (C) At 7.5 kms, charge applied; (D) At 18.5 kms, charge applied
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Strategic river crossings – building a
new bridge in east London
Possible routes
R1
R2
rj
j
k= 5
k= 4
k= 3
i
k= 2
k= 1
1.
2.
3.
4.
5.
Double radial (via city centre)
Inner ring clockwise
Inner ring anti clockwise
Outer ring clockwise
Outer ring anti -clockwise
ri
River Thames
Key to notation
‘k’ are river crossing points
Charges are applied at k1 and k2; k4 and k5 are toll free
A congestion charge is applied to journeys passing through the central charging zone (k3)
Costs based on monetised travel time plus toll or congestion charge
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Images of strategic crossing points in
east London
free
£2.00
Inner ring – Woolwich ferry
Outer ring – Dartford crossing
?
£3.20
Inner ring bridge design
New cable car crossing
Central
London
congestion
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charge £10
Total market capture of old and new
river crossing
15%
Outer ring
radius 25kms
20
Inner ring
radius 12.5
kms
10
15%
In n e r
rin g
20%
20%
25%
y
0
-10
-20
key
O u te r
rin g
-20
25%
-10
0
10
20
Different
locations have
different route
market shares.
Contour values at
any given
location represent
the percentage of
traffic using a
particular route.
The higher the
market share the
busier the route is
expected to be at
that location and
the greater its
influence over
traffic at any point
Im p a ct zo n e fo r n e w b rid g e
x
Im p a ct zo n e fo r o ld b rid g e
N e w a n d o ld b rid g e s
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Should London build a new airport in
the Thames Estuary?
Artist’s impression of new airport and its proposed location in the Thames
estuary about 66 kms from the city centre
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Two attraction problem in an orbital-radial
urban area: Example of two airports
Radial market area, A
Orbital market area B
Orbital
market
area A
Ring
road
Two airports A,B with
slow orbital road
Two airports A,B with
fast orbital road
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The concept of eclipsed market areas and
their importance in locating new airports
Internal
External
External and Internal Eclipsed
Regions for attraction A
Map showing inner and outer eclipse
envelopes for a 3-attraction example.
Shaded areas are eclipsed
The market area of any proposed new airport which is located in the
shaded region of either map would be eclipsed by existing airports
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Introduction of new airport in east
London but will it be ‘eclipsed’ before
it is built?
Radial market
A location on
the east side of
London makes
strategic sense
and would be a
good strategic
fit with the
other regional
airports
area
Locations and market areas for four and five regional airports. The
circle represents the M25 orbital route. Inner and outer eclipse
envelopes are also shown (A = Heathrow; B = Luton; C = Stansted;
D= Gatwick)
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But is the proposed location viable?
Chart shows how the market
share of existing airports adjust
according to the distance of the
location of the new airport
from the city centre.
60%
Market share
50%
Heathrow
40%
Luton
Stansted
30%
New
Gatwick
20%
10%
0%
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39
45
51
57
63
Radius of new facility (kms)
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The new airport would capture
nearly 30% of the geographical
market if it located at or near
the M25 but this would reduce
zero if it were twice this
distance from the centre
(proposed location is 66kms
from the city centre)
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Market areas in orbital radial networks
Outside
boundary
Trips divert through
centre
Inside
boundary
Orbitals
(a)
(b)
Service area enclosed by isochrone situated on a fast
orbital – two cases. The area enclosed by the isochrone
in case (a) is given by:
A  2V AV B t
2
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Tessellating concentric urban areas
with multiple ring roads
Tessellated concentric hypothetical urban areas with
one to five rings and six facilities per ring:
•12.5kms gap between rings
A
B
•Radial velocity 50 kph
•Maximum travel time radius to nearest centre is 15
minutes
•Orbital travel time 3 hours
C
D
•Ring speeds proportional to distance from city
centre
•Inner ring service area 164 sq km; out ring 818 sq
km
E
•Six facilities per ring
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Areas spanned in given travel time
radius
‘All-purpose speed’ in interstitial areas
(a) 50kph
(b) 25kph
(c)
10kph
Where there are a finite number of fast radial routes it may be useful to distinguish
between speeds achievable on the fast routes from the interstitial ‘all-purpose’
routes
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Abercombie Greater London Plan
(1944)
E
B
A
D
C
Arterial (motorway standard)
Sub-arterial major roads
Basic standard
(A)
(B)
(C)
(A) Abercrombie’s arterial system; (B) ‘Tessellated version of Abercrombie; (C)
tessellated version with slower interstitial road speeds. There are ten fast radials
with 5 orbital-radial intersections on each ring
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Does Abercrombie’s ring structure
work?
• Ring B the ‘inner ring’ is of ‘merit’ as is ring D, both of which are
designated motorway standard
• The outer-most ring E could be of merit but it was not designated
motorway standard in the plan
• Ring C, the current N&S circular is not of merit but should be
• Ring A corresponds almost exactly to the current central area
congestion charging zone and has assumed much greater importance
• The analysis also suggests the need for a ring ‘O’ which would be of
approximately 1-2kms radius inside the current congestion charging
zone and pedestrianised. This has been included in the previous slide
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Comparison with today
• The London orbital M25 combines features of
Abercrombie’s two outer rings D and E
• Ring A corresponds with the London congestion charging
Zone
• Ring B the inner motorway ring was abandoned in the
1970s
• Ring C the N&S Circular has been improved in parts but
does not join up
• Ring E exists but is not fully joined up and is not considered
‘strategic’
• A few radials of motorway standard have been
constructed but most terminate at or around the M25
orbital instead of ring B as envisaged
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What’s changed and why was plan not
completed?
•
•
•
•
•
Conflict between high street retailing and accommodation of through traffic in high streets
Conflicted with the preservation of character and built form of local areas
Switch in philosophy from car accommodation to car containment
Congestion charging
Speed limits
Parking restrictions
One-way systems
Local improvements
Public transport improvements
Low emission zoning
Pedestrianisation
Cycle ways
Planning restrictions and land use
Competition from out of town centres e.g. located on or near orbitals
More recently competition from internet retailing and increasing home delivery of goods and
services
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Conclusions
• Urban spatial theory has stalled, not much progress as far as
one can tell
• However, visionary proposals are becoming more
commonplace and are in fashion again
• Theories are needed to validate these visionary ideas and to
inform new proposals and data collections
• Working with different geometries has much to offer and
further to go
• Important that theory does not run too far ahead of practice
and vice-versa
• Use of geometry as a precursor and to explore options can
save money and speed up planning and evaluation
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References
•
Hyman, G. and L. Mayhew.(2008) Toll optimisation on river crossings serving large cities. Transportation Research A. 42(1) 28-47
•
Hyman, G. and L. Mayhew.(2004) Advances In Travel Geometry and Urban Modelling. GeoJournal 59, 191-207.
•
Hyman, G. and L. Mayhew.(2001) Market area analysis under orbital-radial routing with applications to the study of airport location.
Computers, Environment and Urban Systems, Vol 25,195-222
•
Hyman, G. and L. Mayhew (2001) Reassessing Urban Space Using Fast Route Geometry. In Transport Planning, Logistics and Spatial
Mismatch, 5-21. Pion, London.
•
Hyman, G. and L. Mayhew (2002) Optimising The Benefits Of Urban Road User Pricing. Transport Policy Vol 9, 189-207.
•
Mayhew, L. (2000) Using Geometry To Evaluate Strategic Road Proposals In Orbital-Radial Cities. Urban Studies Vol 37, 13, 2515-2532.
•
Hyman, G,.and L. Mayhew (2000) The Properties of Route Catchments in Urban Areas. Environment and Planning B., Vol 27, 843-863.
•
Hyman, G. and L. Mayhew (2000) Fast Route Geometry in Urban Areas. Environment and Planning B., Vol 27, 265-282.
•
Mayhew, L. (1986) Urban Hospital Location. London Research Series in Geography.. George Allen and Unwin, London
•
Hyman, G. and Mayhew, L. (1983) On The Geometry Of Emergency Service Medical Provision In Cities. Environment and Planning A, Vol
15, 1669-1690.
•
Mayhew, L. (1986) Urban Hospital Location, George Allen and Unwin, London.
•
Mayhew, L. (1981) Automated Isochrones and the Location of Emergency Medical Services in Cities. Professional Geographer 33(4),
423-428.
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