CPB

Corporate PartnershipBoard

How the Inaccessibility
Index Can Improve
Transport Planningand Investment
Discussion Paper

Floridea Di Ciommo
cambiaMO, Madrid

CPB

Corporate PartnershipBoard

How the Inaccessibility
Index Can Improve
Transport Planningand Investment
Discussion Paper

Floridea Di Ciommo
cambiaMO, Madrid, Spain

The International Transport ForumThe International Transport Forum is an intergovernmental organisation with 59 member countries. It
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Cite this work as: Ciommo, F.D. (2018), “How the Inaccessibility Index Can Improve Transport Planningand Investment”, Discussion Paper, International Transport Forum, Paris.

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Acknowledgements
The author is grateful to the Barcelona Metropolitan Area and its director of the Strategic Planning
Department Francesc Magrinyá and to the Institute of Regional and Metropolitan Studies of Barcelona
with mobility survey director Maite Perez, who made this analysis possible by providing the Dataset aswell as some valuable discussions. Further thanks to Maurizio De Crescenzo who started analysing thedataset, and the author’s Master thesis mentor, Francesca Pagliara. The author would like to thankIfigenia Psarra for the inspiring discussions during her TEA Cost Action TU1209 STSM at UPC-BarcelonaTech in April 2016. Regular contact with the Working Groups’ chairs who were crucial for TEA Cost Action
development, contributed to developing the theoretical background that made it possible to write this
discussion paper. Special thanks to the Transport Authority of Barcelona (ATM) team and Gianni
Rondinella from cambiaMO who respectively provided data and elaborated maps for assessing the
tramway extension.

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Table of contents
The needs-based approach and the inaccessibility index ................................................................................. 5
Needs-based approach: A methodology based on the inaccessibility index ............................................... 6
The proposed inaccessibility index ............................................................................................................... 6
Interpretation of the index: The case of Barcelona........................................................................................... 8
The selected geographical area: Eastern Barcelona Metropolitan Area ..................................................... 8
The dataset ................................................................................................................................................... 9
Eliciting people’s needs .............................................................................................................................. 13
Potential incorporation into transport planning/assessment frameworks ..................................................... 14
Ex-ante assessment of Sant-Andriá de Besós-Badalona port Tramway extension.................................... 15
The IA index contribution to the BMA strategic plan for decreasing poverty corridors ........................... 16
Conclusions ..................................................................................................................................................... 19
References ...................................................................................................................................................... 20

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The needs-based approach and the inaccessibility
index
Currently, the main framework for assessing transport investment adopts the utility-based approach,including preferences, choices and travel time saving. However, when the assessment is aimed atevaluating equity in transport, the utilitarian approach is not enough. Although costs and time saving areamong the variables to consider, they are not sufficient for evaluating transport projects andinvestments in terms of equity (Martens and Di Ciommo, 2017; Guzman et al., 2013). Other variables
such as the need to carry out specific daily tasks (i.e. health, schools, food shopping, taking care of otherpeople’s mobility) have a growing impact on the evaluation of the benefits of transport projects.
Relevant studies (Currie, 2004; Currie and Sembergs, 2007; Lucas et al., 2016; Guimarães et al., 2017;
Litman, 2017; Di Ciommo et al., 2017) have shown the following:
1.

The transport system is perceived as essential for key human needs in terms of safety andsecurity in health, employment and social stability, particularly among low-income households,
and its excessive economic weight in the household budget may compromise other household
expenditures (health, education, quality of food).

2.

Failing to meet these needs may result in physical, social, geographical and economic social
exclusion.

3.

Observing the real needs of people is very challenging because it can be difficult for them toexpress what they find it necessary and important to improve their quality of life, especially inmobility.

Generally speaking, needs are associated with rights. We have the basic need to have a place to live andwe have the right to housing; we have the need to be in good health and we have the right to healthcare; we have the need to carry out specific activities, therefore the right to mobility. The European
Union has established the right to mobility as a passengers’ right. The right to mobility per se forpotential users who need to carry out certain essential tasks does not exist. The mobility need has not
yet been defined as a universal right. This right to mobility could be expressed on different levels(national, regional, municipal) where the question of mobility directly affects people’s life. The humanneeds associated with mobility could be differently categorised. Some examples of these needs are:existence needs (exercise, health, safety and security, multi-tasking during travel, overcoming distancebarriers to maintain life-opportunities, travel independence, time and monetary saving), relatedness(togetherness, care-giving, norms and social climate), and personal growth needs (self-esteem,competitiveness, self-identity, and self-actualisation with respect to environmental sustainability andfitness) (Alderfer, 1969). This paper is oriented to operationalise the concept of the existence needs.
The notion of needs is directly related to the notion of benefits: estimating the benefits of a person or agroup of people means measuring how much their needs are covered. However, current methodologies
are based on the sum of benefits that are homogenised and do not always provide evidence of unmet
needs. In the current literature, various approaches have been proposed to estimate population© OECD/ITF 2018

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benefits. These benefits may be weighted differently depending on given groups of the population, theirlocation, transport services availability, socio-economic level, age, gender, etc. (Church et al., 2000). The
complexity and the variety of these factors, linked to the fact that they are referring not only toquantitative concepts, but also to qualitative characteristics, make the transport benefits assessment
difficult to define through the current cost-benefit analysis (Di Ciommo and Shiftan, 2017).
Consequently, several indicators which capture social benefits in transportation have been defined overthe last few years. Among them, the most widely used are probably those dealing with the accessibility
concept (Geurs and Van Bee, 2004; Páez et al., 2012; Farber et al., 2014; Wang et al., 2015). The
advantage of accessibility indicators is that they cover several characteristics of the transport-land use
system in one indicator. By doing so, they can provide a comprehensive assessment of the accessibility“service” received by the population (Martens, 2015). The disadvantage of these particular indicators is,however, that they are estimated as a sum of various elements where the diversity of people in terms ofmobility needs is homogenised. Therefore, one of the main objectives of this paper is to define aninaccessibility index which can reveal the diversity of people and their unmet needs. In other words, thedifferences will be highlighted instead of homogenised.

Needs-based approach: A methodology based on the inaccessibility
index
People’s mobility needs are defined as relevant when related to a specific trip, mode, activity and time ofday. Therefore, the reasons why specific needs might not be satisfied can be understood through theactivity itself (i.e. work, study, daily shopping, occasional shopping, health care, and visits to family andfriends, or mobility of care) and its characteristics (i.e. location, travel time) (Psarra et al., 2013). The
definition of needs would indicate to planners and policy makers where to intervene to meet people’s
needs.
The proposed methodology includes two main steps: focusing on the unmet needs related to specificactivities and exploring activity characteristics such as the travel time.
We present a simple tool of diagnosis to verify needs through the joint analysis of merged mobility andsatisfaction survey data related to each user and their trip, characterised by a specific time of day, aspecific mode or chain of transport, and a specific activity to carry out. The starting point is the definitionof the travel time threshold of a specific activity. It represents the travel time with which users are
satisfied when carrying out this activity.
Based on the initial hypothesis that in transport the need is revealed by the lowest degree of satisfactionof the travel time for each needed activity (Arentze and Timmermans, 2009), each typology of trip ischaracterised by the origin and destination, the purpose, the transport mode and the length. Therefore,
each trip typology is associated with an estimated travel time threshold.
The proposed inaccessibility index

This section introduces the inaccessibility index based on the travel time threshold to carry out activities,
with the objective of assessing the equity and social inclusion of given groups of the population living in agiven region of the Eastern Metropolitan Area of Barcelona. Specifically, the paper defines aninaccessibility (IA) index, which evaluates the inaccessibility of needed activities, using the satisfaction
scores of a 10-point Likert scale (which is used for evaluating the Spanish school system), ranging from6

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very dissatisfied to highly satisfied with a given travel time. In this study, the satisfaction of needs refers
to the satisfaction with the travel time to the destination where individuals need to carry out theiractivities. Considering the satisfaction of needs through the proposed inaccessibility index would
ultimately result in a more equitable transport system evaluation, where the main needs of all theimpacted population groups are taken into account.
In particular, the adopted index would include people’s satisfaction with a specific mobility characteristicof the activity they need to carry out such as travel time. When this satisfaction is high, the individualtransmits that her/his need is covered. On the contrary, when this satisfaction is low, the individual willshow that the need is unmet. In this context, the analysis of the mobility survey and trip’ satisfaction will
reveal where public transport networks should be improved to attract potential users who still do nothave access to their needed activities.
The basic idea of the proposed IA index consists in defining a time constraint that limits the set ofaccessible activities using the current transport system, public, private and non-motorised which includes
both walking and cycling. The proposed IA index is based on the idea that inaccessibility indicators canprovide a comprehensive assessment of the accessibility “service” received by the population and used
to elicit the needs of people to reach their activities. Technically speaking, the proposed inaccessibility
index includes two novelties compared to the previous accessibility index: travel time thresholds for eachtypology of trip, and the group of unsatisfied people for each typology of trip.
The starting point is the definition of the travel time thresholds, representing the travel time with whichusers are satisfied when carrying out an activity. Therefore, these thresholds represent the travel time
beyond which an activity is considered accessible by users.
Once the time thresholds have been defined for each trip typology, the IA index can be computed in thefollowing way:𝑚,𝑝,𝑙𝐼𝐴𝑜,𝑑 = 1 −

𝐣

𝒎,𝒑,𝒍
𝒎,𝒑,𝒍
∑𝐧
𝐝=𝟏 𝑻𝑻𝒐,𝒅 ∗∑𝐢=𝟏 𝑵𝑼𝒐,𝒅𝐠∑𝐢=𝟏 𝑵𝑼𝒎,𝒑,𝒍
𝒐,𝒅

(1)

where:
m represents the transport mode; p the trip purpose; l the length; o the trip origin and d the trip
destination.



TT is the time threshold defined for a given trip typology; it is equal to 1 if the travel time is lessor equal than the time threshold. Otherwise it is 0

NU is the number of users making a given trip

n is the number of the considered typologies

j is the number of users which are realizing the same trip and that are satisfiedg includes the number of both groups of satisfied and unsatisfied users, that are carrying out thesame typology of trip.

This index allows us to differentiate between the inaccessible activities and the accessible activities.
Therefore, when the IA index decreases, the accessible activities set increases: a value of the index equal
to zero means that people could reach the activities they need to carry out.

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Interpretation of the index: The case of Barcelona
The selected geographical area: Eastern Barcelona Metropolitan
Area
The needs-based methodology has been implemented as a pilot in some municipalities in the Eastern
Barcelona Metropolitan Area (BMA). The areas were selected following three main criteria: the level ofincome, population profile, and public and private transport level of services.
The four municipalities in the Eastern BMA, which were identified following the three main criteria are
Cerdanyola Del Vallès, Sant Adrià de Besòs, Montcada i Reixac and Santa Coloma de Gramenet. The
Barcelona Metropolitan Area, better known as Greater Barcelona, is a territorial entity composed ofBarcelona and 36 neighbouring municipalities. It has a population of 3 239 337 in an area of 636 km2. The
identified area occupies 10% of the extension of the BMA with a population of roughly 5% of the total of
the Metropolitan Area of Barcelona. The most sprawled out city is Cerdanyola del Vallès with its 30.60
km2, and a population density of 1 883.73 ha/km2, while Sant Adria de Besos is the most compact city
(3.90 km2 with a population density of 8 758.21 ha/km2). Santa Coloma de Gramenet is the city with thehighest population density of 17 017.46 ha/km2 in 7.10 km2 (IERMB, 2012). The income level in this area
is between 21% and 30% lower than in the city of Barcelona, while its population includes between 35%
and 43% of retired people.
These municipalities have been chosen not only because they are close to each other and differ in termsof extension, population profile, population density and income level, but also because the quality of
public services that they present is different, with a reduced number of metro and regional railways
stations (i.e.1-7) and a diverse number of bus lines of between ten and eighteen each.
Because equity and inequality can be better verified in lower scale areas, the proposed methodology has
been implemented in lower scale areas related to the identified centroids. Fifteen specific analysis zones(AZs) have been created. Specifically, six AZs for Cerdanyola del Vallès, three for Montcada i Reixac, two
for Sant Adrià de Besòs and four for Santa Coloma de Gramenet. Each AZ is indicated with the first threeletters representing the name of the municipality and a number (i.e. 1-6). For example, the AZ number 2of Sant Adrià de Besòs has been identified by BES02. Figure 1 represents the identified AZs.

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Figure 1. Eastern Barcelona Metropolitan Area

Source: Own elaboration in QGIS.

The dataset
This study implements the proposed index based on the data obtained from the mobility survey carriedout by the Institute of Regional and Metropolitan Studies of Barcelona (IERMB) over the course of 2013.
The objective of the survey was to identify the mobility patterns of inhabitants on weekdays (Monday to
Friday) in the municipalities of Barcelona Metropolitan Area.
The questionnaire was submitted to users through a computer-assisted telephone interviewing method(CATI) and is divided in three parts: the first part concerns information related to the trips made the day
before the survey (e.g. origin and destination of trips, purpose of trips, length of trips, transport mode,
travel time). If any trip was made the day before, the interview then continued with an evaluation. The
second part includes questions about the user's satisfaction through a 10-point Likert scale. The thirdpart focuses on the users' socioeconomic information (i.e. age, occupation).
This research selected the mobility survey data concerning people living inside the four Eastern
Municipalities of BMA and whose trip purposes include work, study, daily shopping, occasional shopping,health care and visits to family and friends. The considered transport modes are regrouped in three
types: non-motorised transport (NMT) which includes walking and cycling; public transport, which
includes bus, metro, tramway and train; and private transport, which includes cars and motorcycles,
either as a driver or passenger.
The data preparation includes six steps:
1. Selecting the mobility survey data on people living inside a specific area (i.e. Eastern
Municipalities of BMA) and whose trip purposes include work, study, daily shopping, occasional
shopping, health care and visits to family and friends.

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2. Making a preliminary analysis of the new sample, including inhabitants who have their origin anddestination both inside and outside the considered area.
3. Regrouping the filtered data by typology of trip: people with the same trip purpose, transportmode and length of trip were included in the same typology (Di Ciommo et al., 2016).
4. Defining a given time threshold for each of the categories in the above typology, based on theusers’ level of satisfaction.
5. Highlighting the typologies of more problematic trips associated to less accessible activities (i.e.
lower satisfaction with travel time).
6. Finding groups of population that seem to experience less satisfaction when it comes to meeting
their needs.
The methodology of the needs-based approach is then developed in three phases:•

defining the trip typology and time thresholds•

estimating the inaccessibility index for identifying unmet needs•

identifying population groups with unmet needs.

Identification of trip typology and time thresholds

Following the initial hypothesis that a lower degree of satisfaction with a particular characteristic of anactivity (such as travel time) means that the user’s needs are not satisfied, we propose to work on
identifying trip typology and time thresholds.
Time thresholds have been defined using the data from the second part of the mobility survey, where
people were asked to evaluate from zero to 10 their level of travel time satisfaction with their last trip,
and to indicate the duration of this trip.
Users’ level of satisfaction is defined as follows:•High satisfaction for Likert points between 10-8•

Medium satisfaction for Likert points between 7-4•

Low satisfaction for Likert points between 3-0

It has been assumed that a satisfaction level between 7 and 10 (the first two population groups) meansthat the user is satisfied with their travel time. Consequently, this means a higher satisfaction in terms of
their needs. Table #1 includes some examples of trips typologies and associated time thresholds andtheir statistical average, mode, and median values of travel time.

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Table 1. Examples of identified time threshold (TT) (in minutes)
Trip typology

TT Average

TT ModeTT Median

CER04_CER06_2_3_2

18,5

15

15

MON01_MON02_1_1_1

10,16

10

10

BES02_COL03_4_2_3

32

30

25

COL02_BES01_6_3_2

28

25

25

Legend:Each code (i.e. CER04_CER06_2_3_2) includes: origin_destination_purpose_mode_length
1) Origin and destination use the code of identified AZs
2) Purposes refer to work=1, study=2, daily shopping=3, occasional shopping=4, medical=5, visit=63) Modes of transport refer to NMT=1, PUBLIC=2, PRIVAT=34) Length: 0-5 km=1, 6-15 km=2, 16-25 km=3, etc.
Source: Own elaboration from mobility survey, IERMB (2013)

Estimation of the inaccessibility index for identifying unsatisfied needs

The second phase estimates the inaccessibility index. Once the time thresholds have been defined foreach trip typology, the IA index is estimated for people who have shown the need to make a given trip toreach a given activity.
This index allows us to identify the inaccessible activities for specific groups of population. The IA index
evaluates when people can or cannot reach the needed activity, where the need is measured by thelowest satisfaction degree with respect to the current travel time. Upcoming needs-based appraisal
methods in transport indicate the satisfaction of these needs as a measure of equity (Alderfer, 1969).
The pyramid below shows the needs-based approach for equity assessment where the inaccessibility
index estimation is the first step to reveal the unmet needed activities for specific groups of people.
Therefore the implementation of the proposed inaccessibility indicator in the analysis of Eastern BMA
will open up a debate on where and for whom actions should be focused within the selected
geographical area characterised by a lower level of public service, lower income and a population at riskof social exclusion (Cebollada, 2009).

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Table 2. Inaccessibility index estimation
Zone

IA INDEX

MON01

0.356481481

MON02

0.358078603

MON03

0.308823529

CER01

0.475409836

CER02

0.506329114

CER03

0.344827586

CER04

0.441295547

CER050.512345678

CER06

0.216666667

COL01

0.376569038

COL02

0.528037383

COL03

0.531707317

COL04

0.424836601

BES01

0.310126582

BES02

0.265957447

Figure 2. Identification of needs in transport through the inaccessibility index

Unmet needs
and social
exclusion

Lower satisfaction with acharacteristic of the needed
activity (i.e. travel time)

Inaccessibility to essential activities

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Eliciting people’s needs
The third phase is aimed at identifying population groups who need to carry out essential activities. It is a
simple method for eliciting the needs of people who could indirectly express what they find necessary
and important to improve their quality of life. This would indicate where planners/policy makers shouldintervene to help those people meet their needs.
The aim of adopting the needs-based approach is to elicit the needs of people through their low level ofsatisfaction. Following the initial assumption that a lower degree of satisfaction with a particularcharacteristic of an activity, such as travel time, means that the travel need is not satisfied, we findpopulation groups with unsatisfied needs (Di Ciommo et al., 2016). Considering the gender andemployment status of users, the results show that retired men and housewives are the least satisfied
among the other groups (Figure 4).
Figure 4. Least-satisfied needs of retired men and housewives

The analysis of people’s satisfaction shows that in the case of retired users, their need to reach healthfacilities through public transport alternatives is not met (i.e. 62% of respondents assessed negatively
their satisfaction), while the needs of housewives to do daily shopping through the private transportmode are not met either(i.e. 53% dissatisfied). Otherwise, 46% of respondents who answered negatively
about their medical trip purpose are over 65 years old, and retired. Both population groups (theretired-elderly and housewives) cannot satisfy their own needs and thus are in a state of non-equity andat risk of social exclusion.

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Figure 5. IA index for housewives and the retired-elderly

Potential incorporation into transport
planning/assessment frameworks
From an equity perspective, transport policy should be mainly addressed to identify groups of population
so as to increase the satisfaction of their needs to carry out a specific activity. In sum, the degree ofsatisfaction is how users can reveal their needs.
The natural implementation of the needs-based approach is aimed at including the inaccessibility index
in the current transport assessment framework adopted by local authorities. When this framework
includes the cost-benefit or multicriteria analysis of transport projects, the needs-based approach will be
prone to the inclusion of the inaccessibility index in that analysis.
We are implementing the inaccessibility index related to the needs-based approach for two different
transport planning initiatives:
1. The assessment of the tramway extension between Sant’Adriá de Besós and Badalona for theTransport Authority of Metropolitan Region of Barcelona.
2. The contribution to the strategic planning to decrease the inaccessibility of the poverty corridors
in east Barcelona.
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According to the information gathered on actions in the field of mobility and transport projects, a typicalanalysis and a specific diagnosis will be carried out, which will allow us to detect the adequacy andeffectiveness of the current metropolitan policy in transport according to how transport policies andprojects are currently assessed. This analysis is carried out within the Metropolitan Transport Authority
of Barcelona, the transport planning department.
This analysis is based on the fact that transport is mainly a derived demand related to the possibility ofaccessing the daily activities of the population. For this purpose, the indicator of inaccessibility forinhabitants will be estimated and oriented to identify groups of people with less access to their daily
activities. An assessment of the needs of these groups will then complete the analysis.
This inaccessibility indicator is estimated to be integrated into the current assessment framework of theATM. This CBA function can be used as a pilot for assessing transport infrastructures in the Metropolitan
Region of Barcelona and the corresponding transport policies. In particular, data from the mobility
survey and transport projects will be used.
This project responds to the inclusion in the assessment framework of the inaccessibility index.

Ex-ante assessment of Sant-Andriá de Besós-Badalona port
Tramway extension
The extension of the tramway (T4) consists in 1.7 additional kilometres between Sant’Adriá de Besós andthe Badalona port. This urban area includes a logistic and services zone where some space is occupied byinformal housing for immigrants, a gentrified zone and a tourist port sector (Figure 6).
Figure 6. Urban area of tramway extension: Sant’Adriá-Badalona port

Three different buffers at 150, 300 and 500 metres have been designed around the tramway extension
to define the zones including potential groups of population that could benefit from this extension interms of their activity accessibility needs (Figure 7). After this spatial delimitation, two specific mobility
zones have been identified: Zone 2 of Sant’Adriá de Besos and zone 5 of Badalona. The estimation of theinaccessibility indicator in both mobility zones shows an inaccessibility index referring to all transportmodes of 0.26, which is lower than the IA index of the rest of east Barcelona where Santa Coloma deGramenet presents an IA index value of around 0.50.

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Figure 7. Buffers for eliciting tramway extension information

Source: Own elaboration in QGIS (2017).

Figure 8. Current public bus patterns within the potential tramway area

Source: Own elaboration by Google Earth (2017).

The IA index contribution to the BMA strategic plan for decreasing
poverty corridors
The second implementation of the needs-based approach for the inaccessibility index refers to theassessment of certain transport planning strategies aimed at poverty corridors.
The main transport planning strategy of the Barcelona Metropolitan Area includes seven main points:
1. Limit the entry of vehicles according to the ecological tax for outbound roads (i.e. ZBE).

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2. Reduce the use of the private vehicles through a parking policy in which any parking spaces in
the public area have to be regulated within the Metropolitan Urban area, and not only in
Barcelona.
3. Improve the supply of rail transport mainly through measures which improve the efficiency ofthe existing infrastructure or through better organisation of the intermodal nodes such as thestations Torrassa, Montcada and Baricentro, in addition to the existing ones. Rodalies and Metro
can increase their capacity by 40% through some investments.
4. Extend certain metro lines (L3 fins Hospital de Sant Joan de Deu) and tramway lines in strategic
corridors (through the Diagonal connection, the extension from Sant Adrià to Port de Badalona,and from Laureà Miró a Esplugues).
5. Organise a competitive bus network around the poverty corridors which includes BRT corridors(C-245, C-31, B-23, C-58) and the establishment of interurban stations. This new network
involves the Barcelona NXB model as well as other companies adapting solutions to needs.
6. Define a strong Park&Ride policy with centres in Castelldefels, Montgat, Barberà-Baricentro andSant Andreu, which is attached to an extension of the Park&Ride railway station for vehicles and
BitiBi models for bicycles within Barcelona Metropolitan Area.
7. Define a mobility plan around the industrial polygons focused on the urban areas of El Prat-Zona
Frana; Cornellà-Hospitalet, El Pla (Sant Feliu-Molins de Rei), Badalona South andMontigalà,among others.
In the context of the strategic plan, the BMA asked for the definition of a tool to help decision making,particularly around the identified poverty corridors (Figure 9). The implementation of the needs-based
approach highlights in the case of the R4 (N150) poverty corridor that there is a clear correspondence
between the revealed needs of inhabitants and the lower level of services of public transport. The match
between the needs that people state through the mobility survey and the lower LOS of public transport
is fairly consistent (Figure 10 and 11). In this case, the transport planning task is clearly suggested by thebottom-up information: the need of inhabitants is evident, and it is, at least, related to the lack of public
transport.
What is more difficult to show is the potential relation of the causality between lack of public transport
and the socio-economic poverty of the considered area. We should continue with the correlation andinvestigate the other socio-economic factors that could be determinants of the poverty corridors. Morethan anywhere else, this kind of spatial area needs joint and inter-sectorial interventions in terms ofeducation, health, land use and transport planning policies. Transport can solve a part of the problem.

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Figure 9. Identified poverty corridors: A BRT proposal

Low Income population (<50% mediane)

Figure 10. Estimation of the IA index for revealing people’s needs

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Figure 11. Public transport accessibility through the supply side: Frequency, reliability and connectivity

Source: PDU, Urbanism department of AMB (2017).

Conclusions
Following the initial hypothesis that a lower degree of satisfaction with an activity characteristic such as
travel time means that the need of the user is not satisfied, we find population groups to whomtransport policy should be mainly addressed so as to increase transport equity.
The opportunity of reaching activities in given areas is represented by time thresholds, transport
networks location and the users’ level of satisfaction regarding unmet needs. A low satisfaction level inreaching the needed activity means that the needs are not completely satisfied, and that there is somerisk of lower quality of life and social exclusion.
The first results for the low-income part of Barcelona Metropolitan Area show that:•

Policy makers should invest a greater effort to win over vulnerable groups of the population,such as pensioners and housewives, who revealed their unmet needs.

•

The network effect that is to the detriment of low-income social groups when they face a sparse
public rail transport network should motivate planners to design a public transport bus network,
able to be competitive with private vehicles. This measure would be beneficial to vulnerable
groups who advocate easy access to the activities they need to carry out.

•

The inclusion of the inaccessibility index in the current assessment project transport frameworkprovides a way to consider equity in a non-paternalistic approach, and using the needs whichhave been revealed. This new approach has the advantage of including the micro-foundation of
the stated choice preferences, considering groups of people in need. In fact, needs are abroader concept than simply preferences: all people are able to express their needs.

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How the Inaccessibility Index
Can Improve Transport Planningand Investment

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Within the equity in transport framework, this paper will provide an
overview on the rationale of using the needs-based approach for transport
planning assessment. The paper is structured into three parts. First, thepresentation of the needs-based approach using the inaccessibility index.
Second, the interpretation of the index through the case of Barcelona. The
focus will be on how the inaccessibility index allows us to capture relevant
information on the satisfied mobility needs of different population groups(particularly for vulnerable groups of the population) through different
transport modes. Finally, the potential incorporation into transport
planning/assessment frameworks. This section discusses the ways inwhich the index could be implemented in two different contexts: ex-ante
infrastructure evaluation and assessment of a deprived geographic area fortransport strategic planning.