A Study of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE)
by
Elli Maria Papaioannou
A thesis submitted in conformity with the requirements for the degree of Masters of Applied Science Graduate Department of Civil Engineering University of Toronto
© Copyright by Elli Maria Papaioannou, 2014
A Study of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE)
Elli Maria Papaioannou
Masters of Applied Science
Department of Civil Engineering University of Toronto
2014 Abstract
This research presents the design, implementation and results of a survey of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE). The CHOICE survey is a web-based survey that combines RP and SP components, and was designed to collect information of commuting mode choices, housing and neighbourhood preferences along with vehicle ownership choices of households with cross-regional commuters in the Greater Toronto Area. Investigations of the survey data revealed that for small increases in commuting costs people are willing to change to more efficient cars. As commuting costs reached higher levels, participants chose to relocate their home in order to commute shorter distances. This study provides evidence that vehicle ownership and especially residential location decisions are a complex process and are interrelated. The findings of this study show some of the possible reactions of households in the GTA in the face of extreme increases in transportation costs.
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Acknowledgments
This two-year-long journey flew by and I am standing at the end of it today trying to think of all the challenges I faced, all the wonderful and bright people I met, all the things I learned, and all the friends I earned.
First, I would like to sincerely thank my supervisor, Khandker Nurul Habib, for his valuable guidance and genuine care. He is an enthusiastic teacher and a great person who treats his students as his children. I want to thank him for his help, advice and kindness. Many thanks to all my other professors for their important input: Amer Shalaby, Lloyd McCoomb, and especially Matthew Roorda for spending the time and energy as a second reviewer of my thesis.
Second, I want to thank Dimitris Panagiotakopoulos, the programmer who not only helped in coding the survey, but with his patience and experience also played a definitive role in the outcome of the study.
I also want to thank my friends and colleagues within the transportation group at the University of Toronto. Mohamed Salah Mahmoud offered his valuable help and support countless times throughout these two years, and I consider myself lucky for having the opportunity to learn from him. Many thanks go to Adam Weiss for offering his help during the development of the survey. Of course, these two years would not have been the same without my good friends and office- mates: Adam Wenneman and Nico Malfara; you two made my days in that office “brighter”.
Finally, I want to thank my family: my mother and my brother for their support and love, and especially my father who throughout my life has not only been a parent but my mentor and my biggest supporter. Many thanks to my “sisters”: Lindsey, Lida and Theofili for their love and countless sessions of skype-laughter. And last but not least, I want to thank my Toronto-people: Lee, Holly, Jane, Kaisa and Aitor who together with the rest of the crew made these two years the most memorable and adventurous journey of my life.
Elli Papaioannou
September 2014
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Table of Contents
Acknowledgments ...... ii
Table of Contents ...... iv
List of Tables ...... vii
List of Figures ...... ix
GLOSSARY ...... xi
1 Introduction ...... 1
1.1 Research Goals and Objectives ...... 3
1.2 Thesis Layout ...... 4
2 Literature Review ...... 6
2.1 Vehicle Ownership ...... 6
2.2 Transit-pass Ownership ...... 8
2.3 Residential Location Choice and Travel Costs ...... 9
2.4 Web surveys: Advantages and Disadvantages ...... 12
2.4.1 Errors in Surveys ...... 14
2.5 Revealed Preference (RP) and Stated Preference (SP) Data...... 16
3 A Survey of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE) and the Background of the Study Area ...... 18
3.1 Study Area ...... 18
3.1.1 The Greater Toronto Area ...... 20
3.1.2 The Transportation Tomorrow Survey ...... 23
3.2 Survey Sample Design and Target Population ...... 23
3.2.1 Sample Size Determination ...... 24
4 CHOICE Survey Design ...... 26
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4.1 RP ...... 27
4.1.1 Housing Information ...... 27
4.1.2 Socio-demographic and Commuting Trip Information ...... 27
4.1.3 Vehicle Information ...... 29
4.2 SP ...... 31
4.2.1 Experimental Design ...... 31
4.2.2 SP1: Effects of Price Changes on Mobility Tool Ownership ...... 31
4.2.3 SP2: Residential Relocation as a Reaction to Increased Transportation Costs .... 37
4.2.4 Comments on the SP Component ...... 42
4.3 Software ...... 44
4.4 Recruiting ...... 44
4.5 Sample Distribution and Representativeness ...... 44
5 CHOICE Survey Results ...... 48
5.1 RP Descriptive Analysis ...... 48
5.1.1 Household Descriptive Analysis ...... 48
5.1.2 Descriptive Statistics of Individuals’ Characteristics ...... 51
5.2 SP1 Descriptive Analysis: Mobility Tool Ownership ...... 53
5.2.1 Fuel Consumption and Engine Type ...... 54
5.2.2 Vehicle Type ...... 55
5.2.3 Influence of Different Factors on Operation Costs ...... 56
5.2.4 Transit Pass Ownership ...... 57
5.2.5 Relocating Decision ...... 57
5.3 SP2 Descriptive Analysis: Residential Location Choice ...... 59
5.3.1 GTA Overview of SP2 ...... 60
5.3.2 Conclusion of Residential Location Choice Descriptive Analysis ...... 66
5.4 Dwelling Type Choice ...... 66 v
6 Modelling Mobility Tool Ownership and Residential Relocation ...... 68
6.1 Mobility Tool Ownership Model ...... 68
6.1.1 Data Preparation ...... 68
6.1.2 General Model Specification ...... 69
6.1.3 Empirical Analysis ...... 70
6.2 Trade-offs Between Mobility Costs and Residential Location ...... 72
6.2.1 Data Preparation ...... 72
6.2.2 General Model Specification ...... 72
6.2.3 Empirical Analysis ...... 73
6.2.4 Elasticities ...... 74
7 Modelling Dwelling Type Choice ...... 78
7.1 Dwelling Type Model ...... 78
7.1.1 Non Linear Interactions ...... 78
7.1.2 Utility Functions ...... 79
7.1.3 Results ...... 80
8 Conclusions and Future Work ...... 83
8.1 Summary ...... 83
8.2 Recommendations for Improving the CHOICE Survey ...... 85
8.3 Future Work ...... 86
References ...... 87
Appendix A: Survey Software ...... 93
Appendix B: Statistics of Current Home Location and Location Chosen in SP2 by Region ..... 112
Appendix C: Fixed and Variable Costs of all Vehicle Combinations in SP1 ...... 116
Appendix E: Transit Fare O-D Matrix for Scenario 1 ...... 123
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List of Tables
Table 1: GTA Population Change 2006 to 20011 (TTS Data) ...... 20
Table 2: Attribute Characteristics of SP1 ...... 33
Table 3: Car Choice Characteristics ...... 34
Table 4: Number of Total Responses at each Part of the Survey ...... 45
Table 5: CHOICE Sample Representation of Household Attributes Based on TTS 2006 Data .. 45
Table 6: Sample Representation of Individual Attributes Based on TTS 2006 Data ...... 46
Table 7: Recruitment and Response Rate ...... 48
Table 8: Descriptive Analysis of Household Attributes ...... 49
Table 9: Descriptive Analysis of Individuals’ Characteristics ...... 52
Table 10: Home and Work Location Distribution of Sample ...... 53
Table 11: Estimation Results of Linear Regression Model for Operation Costs ...... 56
Table 12: Statistics of Housing Price in SP2 ...... 67
Table 13: Estimation Results of MNL for Mobility Choice in SP1 ...... 70
Table 14: Estimation Results of Binary Model for Leaving Current Home Location in SP1 ...... 74
Table 15: Residence Relocation Choice Elasticity with respect to Increasing Transportation Costs (derived from the results of the binary model in Section 6.2.3) ...... 76
Table 16: Estimation Results of MNL for Dwelling Type Choice in SP2 ...... 81
Table 17: Spatial Location Statistics of York Region Households ...... 112
Table 18: Spatial Location Statistics of City of Toronto Households ...... 113
Table 19: Spatial Location Statistics of Halton Region Households ...... 114 vii
Table 20: Spatial Location Statistics of Durham Region Households ...... 114
Table 21: Spatial Location Statistics of Peel Region Households ...... 115
Table 22: Variable and Fixed Costs of Vehicles in SP1 ...... 116
Table 23: Dwelling Type Price for One-bedroom Units by Neighborhood ...... 117
Table 24: Dwelling Type Price for Two-bedroom Units by Neighborhood ...... 118
Table 25: Dwelling Type Price for Three-bedroom Units by Neighborhood ...... 119
Table 26: Dwelling Type Price for Four-bedroom Units by Neighborhood ...... 120
Table 27: Dwelling Type Price for Five-bedroom Units by Neighborhood ...... 121
Table 28: Qualitative Characteristics of Neighbourhood ...... 122
Table 29a: Transit Fares for SP1 ...... 123
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List of Figures
Figure 1: Errors in surveys (figure reproduced from Groves (2005)) ...... 15
Figure 2: Greater Toronto and Hamilton Area ...... 19
Figure 3: GO Transit system map (source: GO Transit website) ...... 22
Figure 4: Survey design overview ...... 26
Figure 5: RP data model of CHOICE survey ...... 30
Figure 6: SP2 map overview ...... 38
Figure 7: Neighbourhood characteristics and housing prices in SP2 ...... 39
Figure 8: RP and SP data model connections ...... 41
Figure 9: Number of possible choice scenarios ...... 43
Figure 10: Reasons for moving from previous to current house ...... 50
Figure 11: Reasons for choosing current neighbourhood ...... 51
Figure 12: Fuel consumption, car ownership and engine types depending on fuel price in SP1 . 54
Figure 13: Vehicle type choice in SP1 ...... 55
Figure 14: Relocating percentage of GTA regions as a result of SP1 cost increases ...... 57
Figure 15: Home and work location concentrations of CHOICE respondents ...... 59
Figure 16: Home location, work location and SP2 home location choice of Durham residents .. 61
Figure 17: Home location, work location and SP2 home location choice of Peel residents ...... 62
Figure 18: Home location, work location and SP2 home location choice of York residents ...... 63
Figure 19: Home location, work location and SP2 home location choice of Halton residents ... 64
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Figure 20: Home location, work location and SP2 home location choice of City of Toronto residents ...... 65
Figure 21: Residence relocation choice elasticity and weighted elasticity with respect to increasing transportation costs ...... 76
Figure 22: Welcome screen ...... 94
Figure 23: Help map for home and work location ...... 95
Figure 24: Part 1- Retrospective house information ...... 96
Figure 25: Part 2- Household sociodemographic information and typical commuting trip ...... 100
Figure 26: Part 3- Retrospective vehicle ownership ...... 103
Figure 27: Help tab for choosing vehicle category ...... 104
Figure 28: SP1- Mobility tool ownership ...... 105
Figure 29: SP2- Home location choice- Screenshot of main map ...... 107
Figure 30: SP2- Screenshot of the divisions in the selected region ...... 108
Figure 31: SP2- Screenshot of the districts in the selected division ...... 109
Figure 32: SP2- Screenshot of the neighborhoods in the selected district ...... 110
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GLOSSARY
AFV Alternative Fuel Vehicles
CHOICE Car and House Ownership in the face of Increasing Commuting Expenses
CMA Census Metropolitan Area
DEFF Design Effect
GTA Greater Toronto Area
GTHA Greater Toronto and Hamilton Area
MLS Multiple Listing Service
MNL Multinomial Logit
NRCAN Natural Resources Canada
PD Planning District
RP Revealed Preference
RUM Random Utility Maximization
SEM Structural Equation Model
SP Stated Preference
SP1 Mobility Tool Ownership Stated Preference Experiment
SP2 Residential Location Choice Stated Preference Experiment
TAZ Traffic Analysis Zone
TTC Toronto Transit Commission
TTS Transportation Tomorrow Survey
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1 Introduction
Transportation cost changes affect travel behaviour in many ways. These changes can affect short-term decisions and actions of people (e.g. departure time, trip frequency, mode choice), but they can also change people’s commitment to places and activities (e.g. change home location, change work location). According to transportation specialists (Meurs, 1990); (Bhat, 1998), vehicle ownership and residential location choice are two of the most important determinants of travel behaviour and affect among others the mode choice, the trip frequency, the trip distance, and the general travel patterns of people.
Identifying how travel cost changes can affect these decisions is of extreme importance to different parties for different reasons. In the short run and given a small increase in transportation costs, trip makers react by reducing the frequency or the distance of their trips, by altering departure time to avoid congested periods, and by switching to less expensive modes of travel. In situations of higher and longer-lasting increases in transportation costs people will decide to modify their mobility tools (vehicles and transit passes). However, humans are creatures of habit and many of their decisions are defined by it. In particular, when we are examining mode choice decisions, we observe that habit plays a significant role and people insist on choosing their usual mode instead of rationally comparing the alternatives (Idris, 2013). It is, therefore, difficult to capture behavioural changes for short term or small changes in cost.
The first time that researchers noticed a change in this apathy was after the crude oil shock in 2008 (Erath & Axhausen, 2010). The unusual and consistent increase in travel costs led many trip makers to abandon their private vehicles. At the same time, the automobile industry in Canada (which is closely linked to the automobile industry in the US due to the Automotive Products Trade Agreement1) noticed a significant drop in the sales of large vehicles. In 2008 the sales of pickup trucks dropped down by 17%, and large sport vehicles were down 29%. Meantime the sales of subcompact cars increased by 33%, and the Toyota Prius hybrid was among the most popular options with 23% increase in sales (NBC News, 2008).
1 The Canada—United States Automotive Products Agreement, commonly known as the Auto Pact or APTA, was an important trade agreement between Canada and the United States. It removed tariffs on cars, trucks, buses, tires, and automotive parts between the two countries, greatly benefiting the large American car makers. 1
This change reveals the demand for smaller and more efficient mode options in the face of the new cost circumstances. Taking this relationship a step further, one may argue that in case of permanent changes in transportation costs people will reconsider their long-term decisions and possibly change residential location.
These potential reactions could change the mobility and housing reality as we know it today. Altering, what we consider, medium and long-term decisions (vehicle ownership and residential location) would cause inconvenience and commotion to governments, individuals, agencies and private companies, and is, therefore, important to find answers to some of these questions.
Governments would be interested to know how people would travel given the new cost circumstances; with such information they would prepare alternative plans to adjust the urban system and provide solutions for different scenarios. At the same time public transit agencies would have forecasts to adjust their service and their network according to the future demand. Companies from the automobile industry would get a preview of the consumers’ preferences and would target their research and resources towards products that are probably going to be more popular among the public. Real estate agencies and construction companies might get information about the type of residence and the areas of the city that will be in high demand. Finally, individuals will have more accurate information about all these issues and they will be able to make educated decisions about their mobility options and their housing choices.
When examining these issues for the North American reality it is even more important to identify how major cost changes could affect individuals’ travel patterns and mobility-related decisions. The Greater Toronto Area (GTA) is the largest metropolitan area in Canada, and the fifth largest in North America with a population of about 6 million residents based on the 2011 Census. According to the population growth projections of the Ontario Ministry of Finance, the population of the GTA will reach 8.9 million people by 2036 (Ontario Ministry of Finance, 2013). The City of Toronto will grow an approximate 23% by 2036, and the other census divisions of the GTA (Halton, Peel, York and Durham) will experience a significantly faster growth (approximately 1.9 million people by 2036).
The residents of the GTA use primarily their private car for commuting trips and add traffic to the already congested street network. According to the Big Move (Metrolinx, 2008) – the
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regions’ transportation master plan – commuters spend approximately 82 minutes in their cars and travel on average 26 km daily. The only metropolitan-wide transit service – GO Transit – is expensive, not easily accessible, and integrates poorly with the local transit agencies, resulting into a very low share of transit to the modal split (only 16.5% of the morning rush hour trips are taken in transit).
Taking all these issues into consideration and combining the possibility of another oil shock event in the future, it becomes apparent what questions this study is attempting to answer. It is of vital importance to understand how people will react, and what aspects of their every-day decisions they will change in order to face a new reality.
1.1 Research Goals and Objectives
With few exceptions most studies found in literature use aggregate or disaggregate revealed preference data for mobility tool ownership and residential location choices, and are, therefore, incapable of capturing reactions to cost ranges higher than those that were observed at the time. This study is trying to cover this gap by investigating the effects of long-term, extreme increases in transportation costs in the context of North American cities and regions.
In order to collect the data needed for this study a survey of Car and House Ownership for Increasing Commuting Expenses (CHOICE) was designed and conducted among a randomly selected sample in the Greater Toronto Area (GTA). The survey combined revealed and stated preference components, and aimed to collect information about the retrospective residential location, housing and vehicle ownership choices of the households. The stated preference component of the survey collected data of the effects of increasing transportation costs on mobility tool ownership levels and residential location choices. Such data could support investigations about the effects of economic recession, increasing traffic congestion and the possible implementation of pricing policies on the change in urban form (the relocation of households in and out of the GTA).
These investigations are very important for regional planning agencies to make informed decisions and/or evidence-based planning. Analyses and outputs of the CHOICE dataset could allow us to test alternative land use and travel demand policies. These could be used by local
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agencies to examine if their short-term goals are met. In addition, the GTA’s regional transit authority – Metrolinx – could use such information to validate if their transportation demand management policies, and their numerous projects are effective and complying with the long- term objectives of the regions’ Master Plan (e.g: smart growth, mobility hubs, smart commuter program Metrolinx’s Big Move).
The collected data were used to develop a series of models in order to understand and interpret the decisions of GTA households in the past, and to form a better understanding about their intentions and willingness to accept higher costs before changing their current vehicle fleet, and/or residential location. Overall, the thesis aims to improve our knowledge on the link between transportation and land use. The data collected through the CHOICE survey will provide a step towards filling the apparent gap between travel demand modelling and land use modelling in practice.
1.2 Thesis Layout
The thesis consists of eight chapters. Chapter 1 presented a brief introduction of the problem, and the purpose of this study.
Chapter 2 attempts an overview of the research efforts and studies that dealt with the development of models for residential location and vehicle ownership. Main focus is given to studies that investigated these choices in combination with stated preference data and varying cost ranges. Additional literature is provided for advantages of combining revealed preference and stated preference data, and finally a review of the different survey collection methods is presented, highlighting the advantages and weaknesses of web-based surveys.
Chapter 3 introduces the CHOICE survey, the study area and the data collection process.
Chapter 4 includes a detailed description of the different parts of the survey and the experimental design, mainly focusing on the stated preference components of the survey and the design process.
Chapter 5 covers the descriptive analysis of all parts of the survey and is meant to be the first approach to understand the study area and the sample.
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After the first analysis, a more thorough and analytical approach is taken in Chapters 6 and 7 with the construction of a series of models. These models cover the two SP parts and answer to the main questions of this study: how will people modify their mobility tools; when will people move; and where will they move.
Finally, Chapter 8 discusses the findings of this study and the interpretation of the analysis, and concludes with a detailed subsection for future work and recommendations to improve the survey for the second phase of the data collection.
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2 Literature Review
This chapter starts with an overview of studies that investigated vehicle and transit pass ownership. Emphasis is given to studies that examined these choices using stated preference data for increasing travel costs. Subsequently, residential location studies are cited to review what has been found about the relationship between travel costs, and in particular commuting expenses, and house location. Finally, a brief overview of the advantages and shortcomings of web-based surveys is presented, followed by the strengths of combining different data sources for modelling.
2.1 Vehicle Ownership
In developing vehicle ownership models the main challenge that researchers faced, was to identify which mechanisms represent more accurately the true underlying choice process, and how these choices change in response to changing attributes. The first vehicle ownership models focused on different aspects of vehicle purchase, ownership and use. Most of these first models were based on aggregate data and explained vehicle ownership choices at a more generic level, such that of a traffic analysis zone, a region, a state or a country (Stanovnik, 1990). The biggest limitation of aggregate models lies in their incapability to be used in policy-sensitive analyses and their incompatibility with agent-based approaches in transportation modelling (Potoglou & Susilo, 2008).
These limitations led to a more microscopic-level approach and to the estimation of vehicle ownership models based on disaggregate data. The first disaggregate models were based on individual or household level data, and addressed the issues of the number and type of vehicles owned and the explanatory variables that influenced these choices; mainly socioeconomic variables, income, purchase price, and travel opportunities by other modes (Tardiff, 1984). Some examples of the first disaggregate vehicle ownership models can be found in Lave and Train (1979) who used multinomial logit methodology to model choice of car type; and in Hensher et al. (1989), who used a nested structure to model car type, size and quantity choices.
Nolan (2010) found that car ownership started becoming a necessity rather than a luxury over the years, and that the effect of income in explaining the variation of car ownership was declining. In 6
her study Nolan used six-year longitudinal data, and estimated the dynamic decisions of households regarding vehicle ownership. The findings indicated, that while higher income still appeared to affect car ownership in a positive way, the size and composition of the household, and the characteristics of the head of the household (age, gender, whether worker or not) were the most significant determinants in the model estimation.
While these early studies analysed vehicle choices in terms of number and type of vehicles, increasing concern about the environment and the energy consumption led to the inclusion of different engine technologies and fuel consumption in the research questions. Brownstone et al. (2000); Hensher and Greene (2001); Potoglou and Kanaroglou (2007) are some of the researchers that combined RP and SP data in their studies to evaluate the willingness for alternative fuel vehicles (for more information about RP and SP data refer to section 2.5). According to Brownstone et al. (2000), RP data are useful to acquire realistic vehicle size and type choices of respondents and SP data are useful for examining attributes that are not available in the market. Iten et al. (2005) developed an SP experiment to account for the make, type, engine size, fuel consumption and fuel efficiency class of the vehicle.
Similar to Iten et al. (2005), Potoglou and Kanaroglou (2007) collected SP data in Hamilton, Canada to examine the factors and incentives that were more likely to influence a household’s decision towards alternative fuel vehicles (AFV). Potoglou and Kanaroglou (2007) used a nested multinomial logit structure to investigate preferences for body type and engine technology. They found that age, gender, and household characteristics are factors affecting individuals’ willingness to pay for AFV. Interestingly, long-distance commuters were found to be more hesitant to adopt AFV. The main reason for this seems to be the shorter travel range of AFV as compared to gasoline/diesel fuelled vehicles. Other studies that used SP data to investigate willingness to switch to AFV technology can be found at Louviere et al. (2000); Alder et al. (2003); Ewing and Sarigollu (2000); and Dagsvik et al. (2002)
All of these models are able to forecast the demand for different fuel economy policies, and to model the future fuel consumption, but they have their limitations. First, they are incapable of capturing the shifts in car purchase caused by changes in fuel price, but most importantly they examine the choice of each vehicle as independent, even in the context of the same household.
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Bhat and Pulugurta (1998) developed a multiple discrete continuous model, which accounts for multiple vehicles and use levels within the same decision making unit. They used SP data from a Swiss survey about household choices of fleet size and characteristics under different cost schemes. The results showed that households with members that commute farther tend to own more cars; however, they do not favour efficient cars. The authors concluded that inertia effects, in the context of downgrading the size and composition of fleet, cease in the face of drastic changes in cost. In contrast, minor cost changes lead to shifts from gasoline to diesel alternatives. These findings suggest that increasing costs will lead to more efficient alternatives and less energy consumption, but they will not affect the mobility of households (Jäggi et al., 2011).
More recently, Erath and Axhausen (2010) developed a structural equation model (SEM) to estimate the household’s consumption for different fuel types (gasoline, diesel, natural gas) in response to increasing costs. In order to develop the model they collected stated preference data from Swiss households in 2009 by using a novel survey approach. A three-stage questionnaire collected information about the mobility tools (vehicle and transit passes), the housing location and the housing costs of the households. Then the respondent was asked to add the desired mobility bundle for each commuting member based on different residential locations and for increasing gas price scenarios. Finally, in the last stage of the experiment the respondent had to indicate which combination from stage two (residential location and mobility tools) they would ultimately choose. Their investigation showed that older people, frequent public transit users, and people living in less accessible areas react more to higher transportation costs. In contrast, households with more adult members and households with big cars (luxury, sport, SUV) react less to higher costs.
2.2 Transit-pass Ownership
There are many studies that investigate vehicle ownership, but little can be found about public transit pass ownership and use. Even though it should be self-evident that transit pass ownership replaces, to a certain extent, vehicle ownership, there are very few studies that account for this interaction. Relevant studies found that the commitment to a mode affects significantly the use of the respective mode and that consequently strong substitution effects exist between vehicle and transit pass ownership (Simma & Axhausen, 2003).
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This substitutive relationship becomes more evident when fuel prices increase significantly. König and Axhausen (2003) developed a web-based stated preference survey in the framework of the project “Mobiplan” that aimed to understand the travel behaviour of German and Dutch households. The participants had to state the mode choice and mode use based on real-time information about their commuting trip, and housing costs. The collected data were analysed by Darren et al. (2006) and confirmed that the substitution effects between car and transit ownership are significant, and ignoring such relationship may lead to bias in results.
Erath and Axhausen (2010) developed a more advanced version of the same experiment to account for varying price schemes. In one of the parts of the experiments the respondent had to choose the desired mobility bundle (cars and transit passes) for the household, given different travel costs. The results showed that increasing travel costs have a more distinct impact on the type of vehicle choice rather than the mode selected. Respondents were found more likely to downgrade the size and/or the engine technology of the vehicle rather than switch to public transit.
Triggered by the economic recession and the boosted oil prices of 2008, researchers and governments expressed increasing interest in studies that investigate travel behaviour in such occasions, so that they could prepare the system for similar events in the future. The topics in question include short-term reactions of the kind that König and Axhausen (2003) and Simma and Axhausen (2003) analysed in their studies, but also longer-term reactions that could lead to complete changes in travel patterns and in the structure of the urban form.
2.3 Residential Location Choice and Travel Costs
Increasing transportation costs could lead to complete changes in urban form. Unlike the large number of studies investigating the mode shifts and mobility tool ownership changes under increasing transportation costs, investigations about the residential location choice under the same circumstances are rarely encountered. However, residential location choice on its own has been extensively studied. Most residential location studies use longitudinal, revealed preference or stated preference data, whereas a large portion of the residential location studies focuses on the location choice as a result of the decision maker’s lifestyle (Beige, 2008); (Morrow-Jones, 2007). 9
Studies that are based on longitudinal data are incapable of capturing how travel cost changes influence the location choice. On the other hand, studies based on revealed preference (RP) data cannot directly capture information about the mobility costs, since the alternative/non-chosen locations are not sampled. Therefore, the mobility costs associated with the location of a household are subject to many uncertainties. Instead of using the mobility costs themselves, most studies using RP data include accessibility measures as an indirect indication of the mobility opportunities (locations with high access are related to lower travel costs). Bürgle (2006) concluded that only few travel-related variables influence the residential location choice; in particular those related to an individual’s commuting trip.
Employing SP data to analyse residential location choice is considered by many researchers (Hunt, 2001); (Earnhart, 2002); (Kim et al., 2003) to be the most powerful approach, because such formulations overcome the main constraints of RP (multi-collinearity issues and high data requirements). SP data overcome an additional constraint that RP data fail to address; they measure the impact of new policies and they capture behaviour and choices in hypothetical situations, such as changes in transportation costs, toll implementation, congestions pricing, introduction of new technologies etc. Studies from Hunt (2001) and Molin and Timmermans (2003) that used SP data found that in order for a household to downgrade residential unit, a drastic decrease in commute time to work would be required.
However, most studies are in agreement that residential location choice is mostly defined by neighbourhood attributes, housing characteristics, and household composition and demographics, rather than accessibility attributes (Weisbord et al., 1980); (Bhat & Guo, 2007); (Waddell, 2006). Building on that, many studies focused on the different neighbourhood characteristics and housing needs that households have with respect to their lifestyle. For example, households highlighting the accessibility to highways by car, or valuing the parking availability when choosing a residential location implies people heavily dependent on their motorized vehicles. On the other hand, people who value pedestrian and cycling infrastructure, or the availability of transit service close to their home, indicates more active, environment and health conscious individuals. (Walker & Li, 2007); (Mikiki & Papaioannou, 2014). Similarly, Mikiki and Papaioannou (2012) found that people, who are active and environmentally friendly, change more easily from car to other less polluting and energy consuming modes. 10
Finally, residential location choice has been looked at as a decision that is strongly defined by the life cycle stage of the household. Evidently, over a person’s lifetime different factors will have greater influence on the chosen residential location (Morrow-Jones, 2007). Households with children will most likely value the safety of a neighbourhood, the quality of schools, the distance to school, or spacious house units with yard. Older people will probably prefer neighbourhoods with easy access on foot or by transit to facilities, services and shopping areas (Cao et al., 2006).
Although various researchers have covered the area of modelling residential location choices, the influence of cost changes on the choice of residence is yet to be investigated. The crude oil price shock of 2008 revealed the first signs of willingness of households to reconsider their mobility tools –vehicles and public transit passes. In 2009 Erath and Axhausen (2009) collected information based on six scenarios, in order to evaluate the respondent’s propensity to move due to increasing travel costs. These scenarios encouraged the respondent to choose between various residential situations under different housing and transportation cost schemes. A multinomial logit model was used to question the willingness to accept higher mobility costs before changing residential location. The actual model examined the way people perceive transportation and housing costs and how income influences their cost perception. It further explored the relationship between travel time characteristics and residential location choice. Their results indicated that housing costs are perceived to be the most onerous; nevertheless, strong inertia was present before changing spatial location.
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Undoubtedly, the interactions and trade-offs among residential location choice, mobility tool ownership, and travel patterns are of multidimensional and complex nature. Most studies that can be found in the literature focus on one side of this relationship, leaving most of the interactions out of the equation. In particular, while previous research covers extensively the area of car ownership at the individual level, the household level is left unexamined. SP experiments that have been conducted in the past, collected data for a small range of fuel prices, leaving unanswered scenarios of extreme fuel price increases.
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Most residential location studies conclude that neighbourhood attributes are more defining compared to travel attributes when choosing a location, but most of these studies cover a restricted range of travel costs. The example that can be found in the literature ((Erath & Axhausen, 2010) in sections 2.1-2.3) that investigated the interactions between mobility and housing costs under different cost schemes used a novel stated adaptation approach that proved to be successful. However, this study was based on Swiss data and applies to the European reality, where transit attracts a significantly higher percentage of trip makers, and where the land use and urban design differs notably from the North American situation.
This thesis aims to investigate the relationship that underlies between housing and commuting expenses. In particular, the following research questions are addressed:
What are the preferences of each commuter regarding vehicle type and engine technology in each case? What is the tipping point (trade off) between transportation costs and housing costs? What factors play the most important role when choosing a new residence?
2.4 Web surveys: Advantages and Disadvantages
The proposed CHOICE survey designed for this study was conducted via the Internet and it would be beneficial to underline some of the advantages of using web-based techniques as well as the limitations that come with new approaches.
Evolving technology allowed people to respond via Internet and this method led to cost savings for the researcher and time saving for both the researcher and the respondent. According to researchers, (Berge et al., 1996); (Schmidt, 1997); (Zhang, 1999), the greatest time saving of web-surveys comes from the turnaround time, especially when compared to the delay and potential data loss of mail-surveys. Web-based surveys also reduce the input errors from coding the answers into a database (Zhang, 1999), since the collected information is directly stored in electronic format. The greatest advantage, however, is the design flexibility that web-surveys offer (Dillman, 2000); (Zhang, 1999). Web-surveys combined with a dynamic process that includes pop-up instructions, skip logic, and incorporation of attractive features, such as maps and graphics, may increase the respondent’s willingness and motivation to fill the survey
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(Schmidt, 1997); (Zhang, 1999). From a research perspective web-surveys allow the embodiment of specialized software, algorithms and datasets that can improve the validity of the results and the accurate representation of the subject in question.
While the most commonly cited disadvantage of all surveys is the bias due to errors (refer to Section 2.4.1) that occur at the different life-cycle stages of the survey (Couper, 2000); (Dillman, 2001); (Dillman, 1998), there are some disadvantages that are solely associated with web- surveys. Among the survey errors (coverage error, sampling error, measurement error and nonresponse error), nonresponse errors are surprisingly common in web-surveys. Exogenous factors might interrupt the survey process (e.g. internet connection loss), or specific socio- demographic groups may be under-represented or excluded due to limited access to the Internet (people of low education or low income, older people, etc. (Zhang, 1999)). Typical response rates of travel surveys approximate 20%, but some studies suggest that response rates are lower in web-surveys compared to the traditional paper- and-pencil surveys (Crawford et al., 2001); (Sax et al., 2003); (Underwood et al., 2000). One common problem of web-surveys is the variability of the interface appearance. This problem arises due to the use of different web browsers, screen configurations and operating systems, and in practice may result in a problematic appearance or malfunction of the survey (Dillman, 2000; 2001). These problems may result in higher drop-outs (Smith, 1997); (Zhang, 1999), and, therefore, explain the lower response rates of web-surveys.
Web-surveys also deal with various ethical considerations. Data confidentiality and security constitute a general concern of surveys, but it becomes an even bigger challenge in web-surveys. In web-surveys it is more difficult to persuade the respondent about the integrity of the process, and to assert that the data will be safely and anonymously stored and handled. Finally, some people feel that web-surveys are crossing their personal boundaries. Some consider that receiving surveys via mailing lists is an invasion of privacy; and others are concerned about the degree of access that the researcher may have in their private information (e.g. researchers often collect supplementary information without the permission of the respondent: what browser was used to complete the survey, when they started and finished the survey etc.).
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Finally, there is some technical difficulty in developing web-surveys. There are survey design software available in the market (Qualtrics, Surveymonkey,etc) that offer a variety of question types and applications, but they have limits in their flexibility and/or offer a very small portion of their tools in a free trial version, but they are very costly if full access to the application is required. Due to this restriction most web-surveys are developed by programmers and are customized to the needs of a specific survey topic. Over the long run this approach is not cost- effective since it requires the involvement and compensation of specialists, and the result is very case-specific and cannot be re-used for other purposes. The last technical difficulty is the storage location and administration requirement of web-surveys. Web-surveys require a database to store the information on and a server to host the survey. Servers are costly to acquire, are generally hard to configure, and the database setup is a very important part of the process, because it has to be ensured that all the information is properly stored.
2.4.1 Errors in Surveys
The most commonly cited disadvantage in web-surveys, and in all surveys, is the bias due to errors: coverage error, sampling error, measurement error and nonresponse errors. (Couper, 2000; (Dillman and Bowker, 2001); Dillman et al., 1998). Figure 1 illustrates the different sources of errors and the stage of the life cycle of the survey at which they are encountered.
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Figure 1: Errors in surveys (figure reproduced from Groves (2005))
Coverage error in surveys occurs when there is a mismatch between the target and the frame population. Target population is the population that can be covered, in other words the population of inference, while frame population or sampling frame describes the set of population members that has the chance to be selected into the survey sample. Sampling errors result from the non-observational gap between sampling frame and the sample. Sampling error is dependent on the sample size; therefore, larger sample size reduces the sampling error and provides higher quality of data. However, a larger sample size does not eliminate the other sources of error. Measurement errors are the gap between the ideal measurement and the response obtained. Some researchers identified that respondents who completed a paper and pencil version of the same web-survey answered differently (Sax et al, 2003). Therefore,
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suggesting that technology-related surveys experience larger bias due to inaccurate responses. Finally, nonresponse error concerns the non-observed gap between the sample and the respondent pool. In other words, nonresponse error arises when individuals in a sample are unwilling or unable to complete the survey. This error is surprisingly common in web-surveys..
2.5 Revealed Preference (RP) and Stated Preference (SP) Data
The CHOICE survey combined revealed and stated preference (RP and SP) components to collect information about housing and vehicle ownership of households in the GTA. This section offers a brief overview of each data type, their advantages and weaknesses, and the way they are used and/or combined in choice modelling.
RP methods describe the actual market behaviour of respondents based on measured variables; they are, therefore, limited to analysing the effects of existing factors and cannot provide direct information on new (non-existing) alternatives or examine hypothetical situations. SP data on the other hand are based on the intention or choices of respondents in hypothetical scenarios (Ben- Akiva et al., 1994). SP experiments have received increasing attention in the transportation field, where they are used to determine the influence of independent variables on the observed outcome (Louviere et al., 2000). In traditional SP experiments a number of choice scenarios are presented to the respondent. Each scenario describes some alternative choices with a set of pre- defined attributes, where the attributes can take a range of pre-selected levels, and the respondent is typically asked to choose one alternative. In general, the higher the number of attributes and levels involved the more complex it becomes for the respondent to comprehend and respond accurately to the experimental situation presented.
RP and SP data are usually collected in the form of discrete choice observations and provide choice models with data to investigate trade-offs among variables. The ultimate target is to develop models that can forecast future demand, either for existing or for non-existing products and situations. When trying to find relationships and explain non-existing situations/products/choices, RP data are inadequate and only SP data can cover this deficiency. SP data have numerous advantages over RP data: the attribute levels can be extended to cover a wider range; the correlation between attributes can be minimized; the attributes are free from measurements errors; and most importantly SP data can elicit people’s preferences for new 16
alternatives. However, SP data are subject to perception errors, and it still remains to be concluded how consistent they are with actual behaviour. (Ben-Akiva et al., 1994).
Evidently, each method has its advantages and its backdrops and can be respectively applied. However, when combining RP with SP data we create powerful models, where the utility functions have common preference parameters and usually express the trade-offs that the respondents carry out among the attributes they consider most important. When the RP and the SP data come from the same source it is likely that there will be correlation between the random component observations. Ben-Akiva and Morikawa (1990) developed a method that adjusts this correlation and also controls the correlation between different SP responses from the same individual. It is generally believed that stated preference surveys may yield biases and large random errors (Ben-Akiva and Morikawa, 1990). Therefore, using RP data that have similar characteristics as complementary to SP data can minimize or eliminate these deficiencies. Ultimately, joint RP/SP data are considered to increase the statistical efficiency of models and started giving new insight and explanatory power to the developed choice models.
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3 A Survey of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE) and the Background of the Study Area
A survey of Car and House Ownership in the face of Increasing Commuting Expenses (CHOICE) was designed and conducted in the Greater Toronto Area (GTA). The CHOICE survey is a web-based survey designed to collect information about commuting mode choices, housing and neighbourhood preferences, along with vehicle ownership choices of households with cross-regional commuters in the GTA. The multidimensional nature of this topic requires an unconventional approach. The CHOICE survey is designed as a combination of two stated adaptation experiments that are pivoted on retrospective revealed preference information of commuting trips, car ownership and house ownership of the participating households. The survey is software-based and uses actual commuting costs and information of alternative mobility tool ownership, neighbourhood information and home type/cost in the face of increasing transportation costs.
This chapter starts by introducing the study area and other important information about the GTA. Then, the sampling technique and the sample size calculations are presented.
3.1 Study Area
The study area of the CHOICE survey is the Greater Toronto Area (GTA). The GTA covers an area of 7,124 km2 and consists of the City of Toronto (Etobicoke, York, Downtown, Toronto, East York and Scarborough), and the regions of Peel, Durham, Halton and York. The GTA experienced a population growth of more than 12% in 5 years, and as of 2011 has 6,057,400 residents. Figure 2 illustrates the boundaries of the GTA in addition to the City of Hamilton (GTHA).
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Figure 2: Greater Toronto and Hamilton Area
The GTHA is served by nine separately-governed local transit agencies and only one regional transit provider, GO Transit (for more information about GO Transit, refer to Section 3.1.1.1). The poorly integrated transit system makes the cross-boundary trips inconvenient, unattractive and costly. This shortcoming becomes more evident if we take into consideration the large number of cross-boundary trips (approximately 25%) that take place in the GTHA. According to the Big Move2, a commuter spends on average 82 minutes travelling per day. More than 85% of all commuters use their private vehicle and travel approximately 26 km per day (Metrolinx, 2008). These figures combined with the expected population growth in the near future emphasize the importance of this study. The CHOICE survey targeted households located in the GTA with at least one cross-regional commuter.
2 The Big Move is the regional transportation plan published in 2008 by Metrolinx for the Greater Toronto and Hamilton Area. It makes specific recommendations for transit projects and investment strategies. 19
3.1.1 The Greater Toronto Area
The GTA consists of the City of Toronto and the regions of Peel, Durham, Halton and York. The City of Toronto is according to Statistics Canada home to 2,503,281 people, and is the largest City in Canada and one of the most populous cities in North America. After the amalgamation the City of Toronto consists of six districts: Etobicoke, York, Scarborough, Downtown Toronto, East York, and North York. The Region of Peel consists of three municipalities: Mississauga, Caledon and Brampton and is one of the biggest employment centres, after the City of Toronto. Durham Region is the largest region covering 2,523,63 km2 and consists of 8 municipalities/townships: Pickering, Ajax, Whitby, Oshawa, Clarington, Uxbridge, Scugog, and Brock. Halton Region includes the municipalities of Oakville, Halton Hills, Milton, and Burlington. Finally, York Region incorporates the cities of: Vaughan, Richmond Hill, King, Aurora, Newmarket, Georgina, Markham, Whitchurch-Stouffville, and East Gwillimbury.
Table 1 shows the population of each region and respective municipalities based on Transportation Tomorrow Survey (TTS) data for 2011 and 2006 (for more information about TTS refer to Section 3.1.2).
Table 1: GTA Population Change 2006 to 20011 (TTS Data)
Region Change TTS 2011 TTS 2006 City/Township % City of Toronto 2,616,800 2,445,900 6.99% Downtown 737,900 685,300 7.68% York 140,000 142,300 -1.62% East York 115,500 112,000 3.13% North York 649,000 604,400 7.38% Etobicoke 348,100 319,900 8.82% Scarborough 626,300 582,000 7.61%
Halton Region 502,000 422,700 18.76% Burlington 175,900 157,400 11.75% Oakville 182,600 159,700 14.34% Milton 84,400 52,900 59.55% Halton Hills 59,100 52,700 12.14%
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Peel Region 1,297,600 1,119,100 15.95% Mississauga 713,900 648,400 10.10% Brampton 524,200 416,400 25.89% Caledon 59,500 54,300 9.58%
York Region 1,032,700 857,500 20.43% Vaughan 288,400 231,200 24.74% King 19,900 18,300 8.74% Aurora 53,300 45,100 18.18% Newmarket 80,000 72,300 10.65% Richmond Hill 185,500 158,000 17.41% Markham 301,900 249,000 21.24% Whitchurch-Stouffville 37,600 22,700 65.64% East Gwillimbury 22,500 20,500 9.76% Georgina 43,600 40,400 7.92%
Durham Region 608,300 539,500 12.75% Pickering 88,700 84,200 5.34% Ajax 109,600 87,700 24.97% Whitby 122,100 105,200 16.06% Oshawa 149,700 137,500 8.87% Clarington 84,600 74,800 13.10% Scugog 21,600 20,300 6.40% Uxbridge 20,600 18,200 13.19% Brock 11,400 11,600 -1.72% Greater Toronto Area 6,057,400 5,384,700 12.49%
3.1.1.1 Transit Authorities in the GTA
The GTA (without Hamilton) is served by seven local transit agencies: the Toronto Transit Commission (TTC) in the City of Toronto; Miway and Brampton Transit in Peel Region; York Region Transit/Viva; Durham Region Transit; Burlington Transit and Oakville Transit in Halton Region. There is only one regional transit provider, GO Transit, which serves all regions by bus and train. GO Transit fares depend on origin and destination zones, $5.20 being the minimum possible fare that a traveller could pay. The GO Transit fare system is integrated with six out of the seven local transit agencies, but not with the TTC. This creates inconvenience and additional
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charges for most of the cross-regional commuters, as the majority of them travels to the City of Toronto. Figure 3 shows the GO Transit network, which mainly operates in the Greater Toronto and Hamilton area and extends into many communities in the Greater Golden Horseshoe. The GO Transit system covers 450 km by train and 2,760 km by bus, and carried more than 65 million passengers in 2012 (Metrolinx, 2014).
Figure 3: GO Transit system map (source: GO Transit website)
3.1.1.2 PRESTO Card
In 2007 Metrolinx and the government of Ontario started a trial for a smart card fare payment to integrate public transit systems in Southern Ontario. The full implementation began in 2009 and ever since more provinces and agencies are gradually joining the program. The PRESTO Card is an electronic fare payment system, which uses a smart-card technology and can be used with
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most of the transit agencies that operate in the GTA. PRESTO is becoming popular among the cross-regional commuters, since it typically offers a discount fare compared to using cash fares.
3.1.2 The Transportation Tomorrow Survey
The Transportation Tomorrow Survey (TTS) is a survey that is conducted every five years in the GTHA and collects retrospective household trip diary for 5% of all households in the study area. The first TTS survey was conducted in 1986 and the most recent in 2011. In every survey a random sample of the study area is invited to complete the questionnaire. Until 2006 the survey was completed exclusively over the phone, but starting 2011 the respondents had the option to complete the survey on-line. The survey collects travel data for all household members (11 and older) for the day previous to the phone (or web) contact, in addition to some socio-economic and demographic information.
The CHOICE survey was designed to be consistent with TTS data so many of the questions and distributions defined in the following sections are based on TTS 2006 data. TTS 2006 was the most recent data at the time of the experimental design and implemenation of the survey.
3.2 Survey Sample Design and Target Population
The CHOICE survey intended to measure the trade-offs between mobility tool expenses and housing costs that households with cross-regional commuters are willing to make in the face of increasing transportation costs. At the time of the preparation of the CHOICE survey the TTS 2006 was the most recent survey, and consequently its data was used to determine the distributions of the survey sample. In more detail, the origin-destination matrices from TTS 2006 for all commuting trips were used to determine the total number of cross-regional commuters among the five regions. Households with at least one cross-regional commuter were invited to complete the survey. The survey population of the study (cross-regional commuters) is estimated 28,660 commuters distributed in the GTA. Given the large population and the limited resources it is evident that a sample survey is the only feasible alternative.
There are two types of sampling techniques: non-probability sampling and probability sampling. The first provides a fast and inexpensive way to collect the desired sample by using a non- random method; however, it does not ensure a representative sample of the population. The 23
second method is called probability sampling. When employing this method, we randomly select units from the population and avoid selection bias. Therefore, when using probability sampling it is possible to generalize the results to reflect the whole population (Franklin et al., 2003).
The sampling procedure followed for the CHOICE survey was the simple stratified random sampling based on the geographic home location of the population. The five regions of the GTA were the five strata that made up the sample size, as explained in the next section.
3.2.1 Sample Size Determination
The determination of the sample size is essential because it defines the precision of the estimates. The larger the sample size used in a study, the smaller the nonresponse errors, and therefore, the greater the precision of the estimates. There are many factors that should be accounted for when determining the sample size: the appropriate level of precision in terms of the margin of error, the sampling variance that is required, and finally the size of the survey population.
Calculating the initial sample size: For the CHOICE survey we assumed a maximum population variability of P=0.5. Additionally, a margin of error e=0.05 at a 95% confidence interval is used to determine the sample. This means that there is a 5% chance that the randomly selected sample will not produce an estimate within the range of P±e (z=1.96).