Currie 2004
Currie 2004
Graham Currie
A new approach to assessing the performance of public transport in                        • To assess the distribution and quality of public transport
meeting the needs of transport-disadvantaged people in the community                   service provided geographically, and
is described. It reviews previous and current research in this area and                   • To identify any needs gap between community needs and
describes how a new approach has been developed and applied with                       service provision.
Hobart, Australia, as a study area. The approach aims to identify geo-
graphical gaps in public transport provision where travel needs are high                 This paper is divided into four sections: a review of transport
but services are poor or nonexistent. It involves the use of readily avail-            needs gap measurement, a new approach to needs gap measurement,
able socioeconomic statistics to quantify the distribution of needs in the             key findings, and conclusions.
community with a single transport needs index. A public transport net-
work model measures the public transport accessibility to these groups
and a geographical information systems approach is used to display the                 TRANSPORT NEEDS GAP
distribution of the identified gaps between service and needs. The tech-               MEASUREMENT: REVIEW
nique is highly relevant for smaller urban centers where the justifica-
tion of public transport subsidies is largely social-needs–based—that is,              A literature review of quantitative approaches to measuring the geo-
where congestion and environmental benefits of transit are less critical.              graphical distribution of people facing transport needs was under-
It is also relevant to recent work in transport accessibility audits and in            taken by Currie and Wallis (2) and more recently by Nutley (3).
the assessment of community impacts of alternative transit development                 These reviews identified a range of approaches. Key components of
strategies.                                                                            the methodologies applied include the following:
                                                                                 137
138                                                                                                     Transportation Research Record 1895
Voorhees Associates (8), and Moseley (9), which is often termed the        NEW APPROACH TO NEEDS
Lewes approach. In this case, the focus of analysis was rural settle-      GAP MEASUREMENT
ments in East Sussex in the United Kingdom. The scale of transport
needs was identified by examining census records for the number of         Reasons for Change
persons in social groups considered to be needy—for example, peo-
ple living in households with low car ownership. The quality of sup-       The Department of Infrastructure Energy and Resources in Tasmania
ply was measured by examining public transport schedules to classify       was seeking methods to assess the performance of public bus services
access to particular trip purposes, such as shopping, as impossible,       relative to the distribution of travel needs in the community. In 2002,
poor, medium, or good. A needs gap was identified when a settle-           management consultant Booz Allen and Hamilton was commissioned
ment had high concentrations of persons in needy groups and poor           to use the methods developed by Currie and Wallis (2) to investigate
or no access to public transport.                                          needs gap issues in Hobart, the capital city of the state of Tasmania,
   This research aims to combine the assessment of both social needs       which has a population of 192,000.
and the quality of public transport. There is a range of literature on        Some specific issues regarding the Hobart needs gap project
either side of this equation, notably a range of techniques in measuring   required further development of the methodology:
public transport accessibility (10, 11).
   There have been more recent moves to examine the match be-                 • A local area assessment within a major urban area was required.
tween transport needs and the service supply in the United Kingdom         This contrasted with more recent applications of the methodology,
as part of work by the social exclusion unit in relation to transport      which identified needs gaps for settlements as a whole.
(12). These approaches have called for an accessibility audit to be           • The supply side focus of the analysis was on public bus service.
undertaken as part of local transport plans. They compare accessi-         Hence, a more detailed methodology was required to measure the
bility to employment, health care, and education facilities by all         quantity and quality of the service provided, including time-of-day
forms of transport with due consideration given to the distribution        and day-of-week analyses.
of socioeconomic groups that face transport difficulties, such as             • It was hoped to apply geographical information systems (GISs)
people without a car, young people, older people, and people with          to display the results of the analysis graphically to improve under-
disabilities.                                                              standing of the results.
   Accessibility audits mirror earlier approaches proposed by Currie
and Wallis (2). Needs gap assessment first measured needs by the
following:                                                                 Revised Approach
                                                                           Overview of Approach
   • Readily available census and social services information was
used to identify socioeconomic indicators that would measure               In general, the proposed approach combined the needs indexation
the scale of transport needs faced by residents in a local area. These     approach suggested by Currie and Wallis (2) and a more detailed
indicators were sourced from an analysis of the Adelaide House-            assessment of transport supply measurement based on the Lewes
hold Travel Survey (13) by comparing socioeconomic groups                  approach. The latter involved the development of a fairly standard
demonstrating low trip-making behavior.                                    public transport network model that measures the quantity and quality
   • An accessibility measure [in this case, travel distance to the        of public transport provision to a high level of detail. The TransCAD
central business district (CBD)] was adopted to identify locational        transport modeling system (20) was adopted to undertake the network
disadvantage.                                                              modeling. The same system was adopted to display the results of the
   • A single needs score was generated that combines the socio-           analysis with GIS. Analysis was undertaken for Hobart’s 387 census
economic and accessibility indicator to give each location a score         collector districts (CCDs). This is the smallest unit of analysis where
between 0 and 100 (with 100 being the location with the highest of         census data could be collated for the needs analysis. Figure 1 presents
the combined indicator values of all the areas analyzed).                  the key steps in the analysis.
   • The quantity of the supply of transport was measured by devel-
oping an indicator that includes the following:
     – A public transport supply measure: the density of vehicle           Network Supply Modeling
   kilometers provided in the daytime interpeak per square kilo-
   meter,                                                                  A public transport network was constructed from an analysis of the
     – A community transport (or paratransit) supply measure: the          bus routes, stops, and timetables in Hobart. The network model
   number of community transport vehicles supplied by area, and            was similar to those used for transit and multimodal network plan-
     – A taxi scheme usage indicator: the number of persons in the         ning in most cities. In summary, the modeling process involved the
   community who are members of the taxi subsidy scheme.                   following:
  A single supply score was generated by combining the compo-                 • The location of facilities, shops, and so forth for 14 trip pur-
nent indicators and generating an index valued between 0 and 100,          poses was defined (see Table 1).
with the highest score representing the highest level of supply.              • The transport model measured the quality of travel by public
  A needs gap was identified where the needs scores were high but          transport (routes, access and egress times, frequencies, travel times,
supply scores were low. The preceding approach was applied in              and fares) for five time periods including the following:
Adelaide (13). Other applications have been undertaken throughout               – a.m. peak (07:00 to 08:59),
Australia and New Zealand (14–19).                                              – Interpeak (09:00 to 14:59),
Currie                                                                                                                                           139
                     1.
                     1. Service
                        Service Level
                                Level Quantification
                                      Quantification                     2.
                                                                         2. Activity
                                                                            Activity Location
                                                                                     Location Review
                                                                                              Review
                                                   3.
                                                   3. Public
                                                      Public Transport
                                                             Transport
                                                      Network
                                                      Network Model
                                                               Model
                                                                                    4.
                                                                                    4. Area
                                                                                       Area Transport
                                                                                            Transport Need
                                                                                                      Need Measurement
                                                                                                           Measurement
                                         5.
                                         5. Public
                                            Public Transport
                                                   Transport Gap
                                                             Gap Analysis
                                                                 Analysis                          6.
                                                                                                   6. Reporting
                                                                                                      Reporting
     – Evening (18:00 to end of service),                                       Where it was possible to walk directly to the nearest destination
     – Saturday p.m. (12:00 to 18:00), and                                   (without using a bus), this was considered to be preferable up to a dis-
     – Sunday p.m. (12:00 to 18:00).                                         tance of 800 m. Some origin zones were very large and hence walk-
   • The analysis generated a matrix of generalized travel cost              ing to and from buses was considered inappropriate given the lack of
results for 14 trip purposes by five time periods and for 387 travel         routes within these areas. Distances above 400 m were identified as
zones (some 27,000 trip cost outputs).                                       the threshold for feasible walk access to and from buses.
   • For each time period, the transport model measured walk                    Figure 2 presents an example of the distribution of facilities for the
access time to bus stops, wait time, fare and travel time on buses,          pharmacies (or drug stores) trip purpose. It also illustrates the gener-
and walk egress time. Table 2 presents the key assumptions for               alized travel costs output from the model. Dots indicate the location
generalized cost modeling included in this analysis.                         of pharmacies in the greater Hobart region. Shading shows the
   • Where more than one option was available for travel, the lowest-        quality of travel by bus in categories of generalized travel cost (2003
cost path was chosen.                                                        Australian dollars), ranging from low cost (light shading) to high cost
                                                                             (heavy shading). The darkest shade identifies where travel by bus (or
                                                                             direct walk) was not possible. Results are for Sunday afternoon.
                                                                                The output from this step in the analysis is a series of total gener-
    TABLE 1 Trip Purposes Adopted: Bus Travel
    Quality Modeling                                                         alized costs by area to each of the 14 trip purposes. These are then
                                                                             summarized into categories such as trip not possible, very high cost,
         CBD—Hobart CBD                                                      high cost, and medium cost.
         Pools—public swimming pools
         Shops—major groups of shops                                         Area Transport Needs Measurement
         Universities—major tertiary education facilities
                                                                             The methodology for measuring needs involves assembling trans-
         Sports—key recreational sporting facilities                         port needs indicators for a series of areas and defining a single needs
         Pharmacy—chemists                                                   score for each area based on the relative indicator values. Transport
                                                                             needs indicators used in the analysis are identified in Table 3.
         Regional—larger regional shopping centers
                                                                                Accessibility is the only indicator not readily available from gov-
         Employers—larger-scale employers’ main location                     ernment statistics. Accessibility measures the natural convenience
         Schools—major primary and secondary schools                         or difficulty a person is faced with when traveling from home to
                                                                             basic services. It is a measure of locational disadvantage. The acces-
         Hospitals—major clinics and hospital sites                          sibility measure used was the distance traveled to the CBD along
         Food Stores—convenience shopping/local stores                       public roads (there are no rail services in Hobart). This was sourced
                                                                             from a road network model for Hobart with the TransCAD modeling
         Cinema—movie houses
                                                                             system.
         Child Care—site for a child-care center or crèche                      The formula for calculating needs scores is as follows:
         Doctors—individual surgeries or clinics
                                                                             needs score a = ( SI1a × WI1) + ( SI 2 a × WI 2) + L + ( SI 7a × WI 7)
140                                                                                                       Transportation Research Record 1895
                                                                                                                               SUN_PM
                                                                                                                            Cost to Phamacy
                                                                                                                                0 to 10
                                                                                                                                10 to 20
                                                                                                                                20 to 30
                                                                                                                                30 to 40
                                                                                                                                40 to 50
                                                                                                                                > 50
                                                                                                                                Other
                                                                                                                    0           4          8   12
Kilometers
FIGURE 2   Example trip purpose locations (pharmacies) and bus travel quality (total generalized cost) modeling results.
Currie                                                                                                                                                     141
120
                                                                                                                                      Saturday P.M.
                                                  110
  Average Weighted Travel Time Equivalent (min)
100
                                                                                                                                                                                       Sunday P.M.
                                                  90
                                                        Interpeak                                                                                                                           Evening
                                                  80
70
60
50
                                                  40
                                                        A.M. Peak
30
                                                  20
                                                          CBD       Child_Care   Doctors   Cinemas   Employers   Food_Store    Hospitals    Pharmacy   Regional   Schools     Sports      Shops      Pools   University
Trip Purpose
FIGURE 3 Bus travel total generalized cost shown by equivalent travel time by time period and trip purpose.
variable by time period than it was by trip purpose. This demon-                                                                              Figure 5 indicates that Sandy Bay M and Risdon–Risdon Vale A,
strates that the expansion and contraction of the bus network by                                                                           both inner metropolitan areas, owe a large part of their total needs
time period is more significant than its connectivity to local and                                                                         score to the low car ownership indicator, and Claremont and Kingston
regional destinations.                                                                                                                     owe a reasonably high proportion of their scores to high numbers of
                                                                                                                                           people aged 60 or over.
                                                                                                                                              In general, the other very high total needs score areas have high
Distribution of Transport Needs                                                                                                            scores due to high values in all the remaining indicators. This is a
                                                                                                                                           significant conclusion, particularly for the fringe areas consistently
Figure 4 presents the distribution of Hobart transport needs. This                                                                         mentioned so far.
includes a blowup of the areas in inner Hobart. Needs are indicated                                                                           It is also significant that fringe areas score highly not only because
in Figure 4 by the use of shading; darker shades are areas with higher                                                                     of being less accessible, as may be expected, but also because they
needs and lighter shades indicate lower needs.                                                                                             have high concentrations of people with low car ownership, high
   In general, the distribution of needs is patchy, suggesting a scat-                                                                     levels of disability, and so forth. It can be concluded that, in fringe
tered distribution of high and low scores with no particular trend                                                                         localities, people most vulnerable to transport disadvantage live in
toward inner versus outer areas being either high or low scores.                                                                           areas where public transport is more likely to be limited relative to
There are some fringe areas with clear concentrations of very high                                                                         inner city areas.
or high scores including the New Norfolk area and developed parts
of Bridgewater and Gagebrook.
   Fringe areas with concentrations of high needs scores include                                                                           Public Transport Needs Gap Analysis
Kingston; Sorell; and parts of Snug, Primrose Sands, and the South
Arm–Opossum Bay peninsula.                                                                                                                 Figure 6 shows the important needs gap identified in the analysis.
   In general, undeveloped areas have very low needs scores. This                                                                          The heavily shaded areas are those with identified high needs but
is to be expected given low total population levels. Figure 5 shows                                                                        relatively poor quantity and quality of public transport (i.e., where
the size of component indicator scores for the highest-rated needs                                                                         costs of using buses are very high). This analysis presents results
areas. The component indicators represent the true contribution to                                                                         for the weekday a.m. peak. It also provides a summary of access to
the total needs. These component values have already been multi-                                                                           all trip purposes. Figure 6 presents seven sets of needs gap shading
plied by the associated weights and standardized between 0 and 100                                                                         categories. These represent the cases of needs gap identified in
so that the CCD total needs score is simply the sum of these com-                                                                          Table 4. Key conclusions from this analysis are as follows:
ponents. Suburbs have been split into several zones with the same
suburb name plus an alphabetic indicator at the end to provide each                                                                          • There are no areas with the worst-case combination of needs
with a unique zone name.                                                                                                                   and service (i.e., very high needs and no service).
                     Bridgewater/Gagebrook
Sorell
New Norfolk
                                                                                                   Primrose
                                                           Hobart CBD                               Sands
                                                                                                          0     4     8      12
                                                            Kingston                                           Kilometers
                                                                             South
                                                                              Arm
                                                                                                               Total Needs
                                                                                                                Very Low Need
                                                                                                                Low Need
                                                Snug                                                            Mid Need
                                                                                                                High Need
                                                                                                                Very High Need
(a)
Claremont
                                                           Risdon/
                                                         Risdon Vale
       Berriedale
                                                Lenah
                                 New            Valley
                                 Town
Hobart CBD
                                                         Sandy Bay
                                                                                     0    1    2      3
                                                                                         Kilometers
(b)
                                   100
                                   90
               Scaled Total Need   80                                                                                      Students
                                   70                                                                                      Unemployed
                                   60
                                                                                                                           Low income
                                   50
                                                                                                                           Disabled
                                   40
                                   30                                                                                      Aged 60+
                                   20                                                                                      Accessibility
                                   10                                                                                      No car
                                    0
                                                                                    rD
                                                                                       I
rE
                                                                                    rB
                                                                                      G
                                                  tL
                                                                                      B
                                                                                      K
                                         M
lk
                                                                                   le
                                                                                on
                                                                                  lk
                                                                                on
                                                on
r fo
te
te
                                                                                te
                                       y
                                                                            Va
                                                                            r fo
                                    Ba
wa
wa
                                                                          wa
                                                                           st
                                                                           ht
                                               m
No
No
ng
                                                                         ig
                                             re
                                                                       on
                     y
ge
ge
                                                                      ge
                                                                        r
                   nd
                                                      w
                                            a
Ki
                                                                   sd
                                                                    w
                                                                    id
id
                                                                    id
                                         Cl
                                                   Ne
                 Sa
                                                                Ne
                                                                 Br
Br
                                                                 Br
                                                                 Ri
                                                               n–
                                                            do
                                                         is
                                                    Census Collection Districts
                                                       R
               FIGURE 5                      Component indicator share of total needs score (very high category areas).
FIGURE 6   Areas with significant needs gap ratings, a.m. peak (average of all trip purposes).
Currie                                                                                                                                                145
   • The needs gap areas are predominantly on the urban fringe                 CONCLUSIONS
including the most severe needs gap score category.
   • Several large rural zones feature in the medium needs–no ser-             This paper presents a review of approaches that measure the geo-
vice group. This is because they are too large to be effectively ser-          graphical distribution of transport needs and compares this with the
viced by a bus. This group is interesting in terms of needs gap                distribution of public transport service quality. The analysis has
assessment because it is unlikely that conventional bus routes will            developed the concepts of travel needs measurement identified by
ever be able to effectively service these areas. Nevertheless, the             Currie and Wallis (2) by undertaking a more in-depth measurement
analysis identifies medium travel needs, which require some form               of public transport service levels with a public transport network
of public transport.                                                           model in conjunction with a GIS to display results.
                                                                                  The results provide interesting insight into the distribution of
  Some urban areas were identified in the analysis:                            travel needs in the Hobart community. In general, large numbers of
                                                                               people known to have travel issues are located in places with rela-
    • Risdon and Risdon Vale A, in the highest needs gap group of the          tively poor public transport options—not a good combination. These
urban data (high needs–no service): This is a satellite community,             areas lie mainly on the urban fringe.
with many people in the high transport needs group including Risdon               The analysis provides a reliable and defendable basis for identi-
Gaol. The presence of the jail is interesting. It represents a facility with   fying priorities to adjust public transport services or to locate social
large numbers of low-income residents with zero car ownership. This            facilities to better meet travel needs in the community. It is designed
is the type of facility the needs measurement technique will highlight.        to be easy to apply with usually readily available census and transport
However, classification of inmates as representing examples of high            modeling tools.
transport needs may be questionable.
    • Claremont L, in the mixed very high or high needs and very
high or high cost group: This area has significant development,                ACKNOWLEDGMENTS
including retirement homes around a peninsula with poor bus service
                                                                               Parts of this paper are sourced from a paper by Currie et al. (21). The
levels.
                                                                               author thanks David Enright, Craig Hoey, and Darryn Paterson for
    • Dynnyrne–Tolmans Hill B, also in the mixed very high or high
                                                                               their permission to use this material in this report and for their input
needs and very high or high cost group. This zone straddles the
                                                                               to the research. The author also thanks Tony Richardson and Rita
southern outlet highway in hilly terrain. There are pockets of resi-
                                                                               Seethaler for their support and encouragement with this paper and
dential development along short cul-de-sac side roads, which would
                                                                               Geoff Rose and John Clements for assistance in reviewing the
be very hard to service by bus. Walk distances to services in these
                                                                               document.
areas are too far for reasonable access to bus stops.
    • Geilston Bay A, in the medium needs–no service group: A
large zone on the shore of the River Derwent with essentially a rural          REFERENCES
residential distribution. It includes relatively remote settlements like
Store Point without bus access.                                                 1. Booz Allen Hamilton. Hobart Needs Gap Analysis. Final Report. Trans-
                                                                                   port Policy Division, Department of Infrastructure Energy and
   The analysis revealed that there was little difference in the distri-           Resources, Hobart, Tasmania, Australia, 2003.
                                                                                2. Currie, G., and I. Wallis. Determining Priorities for Passenger Transport
bution of needs gap occurrences by time period. Although public
                                                                                   Funding: The Needs Assessment Approach. Proc., 17th Australasian
transport service levels fall on weekends and evenings, this does not              Transport Research Forum, Canberra, Australia, 1992.
affect the locations that have a needs gap. Instead, it affects the             3. Nutley, S. Indicators of Transport and Accessibility Problems in Rural
severity of the needs gap. Hence, a severe needs gap area may have                 Australia. Journal of Transport Geography, Vol. 11, 2003, pp. 55–71.
better service in the peak, but it is still poor relative to other areas.       4. Colorado Department of Transportation. Transit Needs and Bene-
                                                                                   fits Study. LSC Transportation Consultants, Inc., Tahoe City, Calif.,
   The distribution of areas with a needs gap did vary by trip pur-                1999.
pose. The main factor was the distribution of trip purpose land use             5. Montana Department of Transportation. Montana Rural Passenger
locations. For more localized facilities, such as access to a local                Needs Study. LSC Transportation Consultants Inc., Tahoe City, Calif.,
store, it was less common to identify a needs gap. For trip purposes               March 2001.
                                                                                6. National Personal Transportation Survey. U.S. Department of Trans-
with single or a few sites (e.g., the CBD, universities, or hospitals),            portation, Washington, D.C., 1995.
the travel task was more onerous and hence a needs gap was more                 7. Searle, G. Value for Money from Rural Public Transport Subsidies:
likely to occur.                                                                   A Summary of the Lewes Approach. In Transport Subsidy Policy
146                                                                                                             Transportation Research Record 1895
      Journals (S. Glaister, ed.), U.K. Department of Transport, Lewes,        16. Travers Morgan. Local Community Transport Pilot Project Stage 1:
      United Kingdom, 1987.                                                        Demand Estimation. Director General of Transport and Home and Com-
 8.   Martin & Voorhees Associates. Lewes Area Public Transport Study—             munity Care Program, South Australia, Adelaide, 1990.
      Final Report. ECLRT Division of the Department of Transport, in con-     17. Travers Morgan. South West Corridor Community Transport Study.
      junction with East Sussex County Council Highways and Transportation         Department of Transport, Western Australia, Perth, 1990.
      Department, London, 1981.                                                18. Booz Allen Hamilton. Mornington Peninsula Public Transport Strat-
 9.   Moseley, M. J. Accessibility: The Rural Challenge. Methuen & Co.,            egy. Frankston City Council, Mornington Peninsula Shire Council, and
      London, 1979.                                                                the Department of Infrastructure, Canberra, Australia, June 1997.
10.   Kerrigan, N., and D. Bull. Measuring Accessibility: A Public Transport   19. Booz Allen Hamilton. Potential Initiatives for Improving Public Trans-
      Accessibility Index. Environmental Issues Selected Proceedings of Sem-       port in Regional Queensland. Queensland Transport, Brisbane, Australia,
      inar B, Public and Transport Research and Computation Summer                 Oct. 1998.
      Annual Meeting, London, Sept. 1992.                                      20. TransCAD. Caliper, Newton, Mass., 2003. http://www.caliper.com/
11.   Jordan, C., and S. Nutley. Rural Accessibility and Public Transport in       tcovu.htm. Accessed June 26, 2003.
      Northern Ireland. Irish Geography, Vol. 26, No. 2, 1993, pp. 120–132.    21. Currie, G., D. Enright, C. Hoey, and D. Paterson. Quantitative
12.   Making the Connections: Final Report on Transport and Social Exclu-          Approaches to Needs Based Assessment of Public Transport Services—
      sion. Social Exclusion Unit, Office of the Deputy Prime Minister, Lon-       The Hobart Needs Gap Study. Australasian Transport Research Forum,
      don, United Kingdom, Feb. 2003.                                              Wellington, New Zealand, Oct. 2003.
13.   Strategies to Overcome Transport Disadvantage. Department of Prime
      Minister and Cabinet, Social Justice Research Program into Locational    The views expressed in this paper are those of the author and do not necessarily
      Disadvantage, Canberra, Australia, 1992.                                 represent those of Monash University, the Department of Infrastructure Energy
14.   Travers Morgan. Mobility Study. Report for the Urban Transit Author-     and Resources, or Booz Allen Hamilton. Any errors are the responsibility of the
      ity, New South Wales. Urban Transit Authority, Sydney, Australia,        author.
      1989.
15.   Travers Morgan. Palmerston North Public Transport Strategy. Palmer-      Publication of this paper sponsored by Transportation Planning Needs and
      ston North City Council, Palmerston, New Zealand, 1989–1990.             Requirements of Small and Medium-Sized Communities Committee.