A SYSTEMATIC APPROACH FOR QUESTIONNAIRE DESIGN ON ...

Journal of the Eastern Asia Society for Transportation Studies, Vol. 7, 2007

A SYSTEMATIC APPROACH FOR QUESTIONNAIRE DESIGN ON NEW TRANSIT SYSTEM IMPLEMENTATION IN DEVELOPING COUNTRIES Thillaiampalam SIVAKUMAR Doctoral Student Graduate School of Engineering, Yokohama National University 79-1 Tokiwadai, Hodogaya-ku,Yokohama 240-8501 JAPAN Fax: +81-45-339-4031 E-mail: [email protected]

Toshiyuki OKAMURA Associate Professor Graduate School of Engineering, Yokohama National University 79-1 Tokiwadai, Hodogaya-ku,Yokohama 240-8501 JAPAN Fax: +81-45-339-4032 E-mail: [email protected]

Fumihiko NAKAMURA Professor Graduate School of Engineering, Yokohama National University 79-1 Tokiwadai, Hodogaya-ku,Yokohama 240-8501 JAPAN Fax: +81-45-339-4033 E-mail: [email protected] Abstract: Developing countries are nowadays considering exclusive or semi-exclusive transit system implementation. Such systems need to be planned well; attractive to car-owners and affordable to the transit captive users. Therefore, survey becomes essential to grasp preference from all segments of potential users. However, in developing countries, their response for questionnaire survey using hypothetical questions is less reliable because of users’ lack of knowledge about such transit systems and trading-off in hypothetical questions. This study aims to propose a systematic approach for questionnaire design in the contest of developing countries. Two different surveys with hypothesis system (BRT for Sri Lanka) were conducted: (1) System explanation ways of with and without pictures in questionnaire; and, (2) Level of complexity of the hypothetical questions. This study concludes that, in developing countries, questionnaires need to be attentive in questionnaires design. Even if questionnaires are conceptually same, few structural changes affect users’ response considerably. Key Words: Public Transportation, Questionnaire design, BRT

1. INTRODUCTION Cities in developing countries are facing severe transportation related problems due to rapid growth in economy, urbanization as well as migration of people to cities. These countries are nowadays started considering exclusive or semi-exclusive transit system like MRT, LRT, or BRT as a solution to these problems. Such new transit systems (NTS) essentially need to be well planned so that the car-owners (high income group) find it attractive and, at the same time, it is also be affordable to transit captive users (low income people) because, possibly, such NTS will utilize available road space or replace few existing services. Therefore, survey is strongly needed and it must grasp preference from all segments of potential users. However, their response from questionnaire survey using hypothetical questions, which is the only one possible way to grasp preference on hypothesis system (not yet in operation), is less reliable in developing countries because (1) Such systems are very new to users in developing countries and they do not have knowledge about NTS; and, (2) Users are never/rarely experienced with answering hypothetical questions (scenarios) and sometimes, even to

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general questionnaire survey. There are many challenges which have to be considered in questionnaire design with hypothetical situations as far as developing countries are concerned. Three crucial items are focused by the authors in this study: (a) Variance of respondents is large and therefore, covering all segment of group into the survey is tactfulness; (b) Literacy meant by inexperience and/or lack of knowledge of completely new transit system; and, (c) Literacy meant by inexperience and/or lack of understanding trade-off situations exist in the hypothetical questionnaires. Respondent variance is high thus behavioral difference is also high across segments. Therefore covering all segments of potential users into the survey and grasping their response is difficult, however, necessary. For an example, by income segment, majority of people belongs to medium or low income group. Shifting these low income people from conventional bus and switching the high income group from car usage to NTS is a significant and necessary strategy. Questionnaire survey in developing countries faces many problems and some of them are; illiteracy, unfamiliar terms associated with language, lack of sample frame therefore respondent selection, social-religious-cultural norms, suspicious about the purpose of survey, response reliability, and achieving users understanding without interviewer bias (Jones, 2003). Nowadays, considering the capability of handling hypothetical situation, stated preference (SP) technique has become popular and is commonly used in the field of transportation on implementation of NTS (Kuklys, 2002; D’Arcier, 2000 etc.). Sanko (2001, 2002) depicts basics of SP in simple way and describes ‘choice-based SP’. Recently, there are some studies made on developing countries based SP survey. Alvinisyah et al. (2005) also conducted SP survey on Jakarta busways. Zhang (2003) and Fujiwara et al. (2003, 2004) carried out hypothetical studies in Myanmar. These all studies are contributed more on model developments than data itself. Overall, there are many studies done on hypothetical questions and most of the works are credited to its model sophistication. Therefore, suitable approach to grasp more reliable data is still lacking in academic research contest as far as developing country are concerned. Richardson (2001) also describes that “to date, data collection process not commensurate well to fit to those well sophisticated models developed so far”. Therefore, this study attempts to develop a systematic approach for questionnaire design on implementation of new transit system in developing countries to grasp users’ actual/reliable preference. In developing countries, higher transit dependent population and limited finance increasingly attract the system BRT beside its stage developments feasibility towards rail based systems (Leal et al. 2003). This study considered BRT as a case system for the city of Colombo, the largest city of Sri Lanka, as she is also considering BRT for near future. Though there are many forms of SP survey design exist, in the field of transportation, the common way of presenting SP scenario is giving a defined number of alternatives with some selected attributes and their value. In this study, modes of existing bus and hypothesis mode of BRT were considered and compared, and the following attributes were selected with attributes levels of at most three; travel time, fare, travel time variance, and comfort. Former two are very common and basic attributes while the later two were considered due to the selected system of BRT which clearly differs from conventional bus service in terms of punctual and comfort. Using these attributes and their levels, alternatives were generated using design of experiment (DOE) method. Then the scenarios were prepared by placing a set of four of those alternatives generated by DOE. In order to explain the NTS (here BRT) to the respondents before they attempt to face scenarios (hypothetical questions), the system explanation was given in the paper based 1665


questionnaires prior to scenario page by comparing some system elements of BRT with that of existing bus (E.Bus). By considering the aforementioned two main problems (in the first paragraph), responsible for less reliable response, this study imposed two different surveys for comparing; (1) System explanation way (Media) in hypothetical situation using with/without pictures and (2) Two different level of complexity (LOC) in terms of number of alternatives per each choice. These surveys have been carried out along a potential corridor of Gale-Road in Colombo, the largest city of Sri Lanka. In order to overcome the language barrier, the questionnaire has been translated to all three official language of Sri Lanka (Singala, Tamil, and English). These two studies were conducted in September 2005 and in September 2006 respectively at the same selected study area.

2. WORLD IMPROVED NEW TRANSIT SYSYTEM AND BRT DEFINITION There are many examples in developed countries for this kind of NTS. The authors tabulate some example cities and its improved transit systems. Table 1 and Table 2 show some examples for rail based system of LRT/MRT/Monorail in Asian developing countries and BRT/Guided bus system around the world respectively. Table 1 Example for LRT/MRT/monorail system in Asian developing countries System Country City Kuala Lumpur/ [Kelana Jaya Line-29km (2004)], [Sri Malaysia Petaling Line-15km ], [Ampang Line-15km] Manila/ [Yellow Line-15km], [Purple Line-13.8km], Manila/ Philippines LRT/ [Metrostar-17km] MRT/ Calcuta/ [Calcutta Metro-16.5km], Delhi/ [Delhi MetroSubway India 65km (2002)] Thailand Bangkok/ [Skytrain (1999)] China Beijing, Tianjin, Shanghai, Guangzhou, Shenzhen, Dalian Kuala Lumpur/[KL-8.6km (2003)], [Putrajaya], Malaysia [SunwayCity] Monorail China Chongqing [17.4km (2005)]

System

BRT/ Guided Bus

Table 2 Typical example cities for of BRT/Guided Bus system Country City Brazil Curitiba/[Integrated network] etc. Colombia Bogota/[TransMilenio (2000)] Ecuador Quito/ [Trolebus] Canada Ottawa/ [Transitway], Greater Vancouver/ [B-Line] Japan Nagoya USA Boston, Massachusetts/ [Silver Line (2002)] Australian Adelaide/ [O-Bahn Busway], Brisbane and Sydney China Kunming/[5km(1999)], Shijiazhuang, Beijing, Hangzhou Indonesia Jakarta/ [TransJakarta] Korea Seoul

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Rail based systems are considered as superior transportation solution in many big cities. However, in developing countries in general, many of these plans have not been executed yet due to its unbearable capital cost. Recently, the BRT has become popular urban transit mode in developing world as high-capacity and reliable transit system as rail based system with much less capital cost. There is not huge difference between LRT and bus service with few improvements on number of passengers carried on a single corridor (Yabe, 2004; Yabe, 2005). There are numerous studies and review works starting from South American cities (Curitiba and Bogota) to the recent BRT system in developing region (TransJakarta, Indonesia). They all show their success stories and strategies (ITDP, 2003; Hook and Ernst, 2005). Though there are many benefits proved on BRT over other mass systems, there are some key considerations on its implementation in developing countries. Preparing proper master plan, managing road space limitation, existing uncontrolled land use, and political issues are few of them (Kenneth, 2000). Revealing these success stories, beside Table 2, the following cities are currently in BRT planning process: Shanghai, Chengdu, Chongqing, HuaiAn, Xi'an, Xiamen in China; Delhi, Bangalore, and Pune in India; Bangkok in Thailand (16.5Km); Colombo in Srilanka; and Hanoi and Ho-Chi-Minh City in Viet Nam (Limanond and Pardo, 2006). There are several definitions of BRT. For example, Diaz and Schneck (2000) defined BRT as “distinct from conventional bus transit in a way it combines technology, the operational plan and the customer interface to create higher quality of service”. Whereas TRB (2003) defined it as “rubber-tired light rail transit (LRT) but with greater operating flexibility and potentially lower capital and operating costs”. Definitions by many researchers and practitioners vary broadly and according to its purpose. Walter and Matthew (2003) grouped BRT into four stages of deployment based on examples from developed countries and their infrastructures, but didn’t intend to define the BRT. Therefore, the authors categorize BRT into three types based on developing countries’ capability of stage implementation and users understanding, as given in Table 3. Table 3 BRT categorization according to its elements Type 1 Type 2 Type 3 ¾ Some means of separation from mixed ¾ Additional priority ¾ Sophisticated ITS traffic measures • Signal priority • All along or partially • At at-grade intersection • Vehicle tracking • Bus lane, by road marking/ bit • Passenger information • Real time raised median at station and onboard passenger ¾ Some means of quick boarding & • Modal coordination information alighting (Operation & payment) • Enables pre• Pre collection of fare ¾ Feeder system, Park & planed trips • New low-floor bus Ride (web based) ¾ Unique appearance of bus, stops, lanes

3. SURVEY 3.1 Selected City: Colombo-A Comparison to Other Developing Countries The city of Colombo, the largest city in Sri Lanka, has been chosen as a potential and feasible city to study on newly implementing NTS. An overall country profile is given in Table 4 and its shows the share of selected items of Colombo Metropolitan Region (CMR) over the island of Sri Lanka.

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Table 4 Basic characters of Sri Lanka and Colombo Item Sri Lanka CMR Percentage (%) Land Area (Sq. Km) 65,610 3,593 5.73 Population / (Million) 19.7 5.4 28.83 Number of vehicle (2003) 2,097,166 936,804 44.67 Number of Buses (2003) 68,817 26,866 39.04 GDP /(Billion USD) 23.5 GDP growth rate / (%) 6.0 GDP Per Capita /(USD) 1,200 Gasoline (1L)/(SL Rs) ; Petrol= 92 and Diesel= 60 Gas (12.5 Kg LPG) /(SL Rs) ; 960 (1 USD=100 SL Rs) Source: Bureau of South and Central Asian Affairs, U.S Department of State (Unless otherwise stated, information is as of 2005). Generally in developing countries, deviation in socio economic variables like literacy and income are very wide but in the case of selected city of Colombo, the income distribution is comparably narrow and gets concentrated peak in the middle. Its mean higher percentage of people fall under middle class by income and less people fall either under high or low class of income. Whereas the literacy (by schooling) of the people is considerably high (91.6% by year 2002) compare to other South Asian countries. The literacy does not dictate transportation related terminology and/or NTS knowledge. However, it is expected by authors that, because of their higher literacy ratio, in Colombo, hypothetical questions would be feasible using appropriate questionnaire design incorporating proper system explanation. The bus service is provided by both government and private sectors and the number of busses is not controlled. Therefore, enough buses are in operation and in fact cent-war (competing and trying to earn every single passenger) exists like many other developing countries and it leads to less waiting time for buses (at most 5min) but not in-vehicle time. Its very common phenomena that public transportation mode share is high in developing countries as many of the users are captive. In the case of Colombo, it is even more higher because even car owners uses public transportation for their daily working trip due to high gasoline price and less fare of at most 30Rs (0.3US$) from any city skirt. Para transits exist in many developing countries as formal and non-formal mode of transpiration and some of them are comparably attractive even among poor people for shorter as well as emergency trips. Similarly, three-wheeler (called “Auto” in Sri Lanka and India) is very common and easily available para-transit in Colombo and people use it quite often. Some people use motorbikes too. Therefore, these para-modes could be turned out as feeder services to main line (when planning for line-haul) to support feeder buses. In this way, the mode can be shared and also, para-modes’ entrance into main line could be prohibited. 3.2 Study Area The both household questionnaire surveys (Media and LOC) were conducted at Colombo, along a potential corridor of Gale-Road, which connects Colombo core area (CBD) and south suburban area called Panadura as shown in Figure 1. The selected corridor is the only one major line from south suburban area to Colombo core. The section between Moratuwa (a city along this corridor, as shown in Figure 1) and Colombo core suffers worst traffic jam during peak hours, both in morning and in evening. That is the main reason this location has got authors’ interest. The land use along this corridor is mixed with commercial activity and 1668


residential areas. Regions of Dehiwale & Mt. Lavenia, as shown in Figure 1, were selected as survey areas.

Dehiwale & Mt.Lavenia

Figure 1 Study area (Colombo) and selected corridor 3.3 Methodology Questionnaire design conceptually consists of many factors such as: questionnaire contents; physical design; and types, format, wording, ordering, and instruction of question (Richardson et al., 1995). Though survey design generally covers all these factors, in this study physical design is given more weight. Based on this research hypothesis, two different alterations have been planned. One is in system explanation way (Media) presented just prior to SP scenarios in questionnaires. The other one is physical rearrangement of alternatives in SP questions in such a way the apparent level of complex (LOC) of SP question has been rearranged. These two studies were conducted in a time series of September, 2005 and September 2006. Residents were asked to choose their preference based upon their trip to Colombo core (Pettah) along the corridor from their household. In the Media-study survey, a system explanation is given prior to scenarios, as previously mentioned, with two different medias: (a) Written expressions alone (without-image); and, (b) Same written expressions with relevant pictures also (with-image: Figure 2) to study the media effect by comparing the existing bus (E.Bus) and the BRT elements. Therefore, in both cases, the questionnaire is exactly same other than one is with image and another is without image. The hypothetical questions were given with six scenarios. Each scenario carried four alternatives (Scenario x Alternatives x Attributes = 6 x 4 x 4) as well as some other revealed preference type of questions and personal attributes. In order to observe the system explanation effect purely due from explanation media, this study used same questions for all respondents (where SP design of this study modified purposely from typical SP in which question are given randomly) and drop-and-pick-up technique to eliminate interviewer’s verbal demonstration as it may intrude user’s preferences. A respondent receives either “withimage” or “without-image” type of questionnaire. From now onwards, this “with and without image” comparison study will be referred as “Media-Study”.

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In the LOC-study, in order to compare the effect of question complexity levels, in terms of number of alternatives per each choice set. The hypothetical questions (SP) in the questionnaire of this survey contain two portions. The first portion of the hypothetical questions is similar to the previous survey where alternatives were selected in the same way as before, but this time, travel time variation attribute excluded, as this attributed found to be less familiar. Therefore, in this LOC survey, only three attributes (Travel time, Comfort, and Fare) were included as shown in Figure 8. The hypothetical question was given with four scenarios (reduced to four scenarios to manage the questionnaire length) with each scenario carrying four alternatives (Scenario x Alternatives x Attributes = 4 x 4 x 3) as well as some personal attributes. The second portion of the hypothetical questions has been designed by picking one scenario out of four scenarios from the first portion (Figure 9). The four alternatives of the selected scenario were rearranged to form a sequence of pairs (similar to binary choice game cards). Therefore, one scenario (one choice out of 4 alternatives) will make series of pairs (4 pairs; 4 choices). Because of questionnaire length, in this survey only one scenario has been rearranged and compared. In the first portion, four alternatives were given simultaneously per scenario whereas, in the later portion, sequences of pairs were given. The levels of complexity assumed to be depends on number of alternatives per scenario (trade-off complexity). Thus, first portion is assumed to be complex while second portion apparently less complex respectively for respondents to choose. These two LOC are named as “simultaneous-set” and “sequential-pairs” in this paper. A respondent receives both simultaneous-set and sequential-pairs. From now onwards, this simultaneous-set and sequential-pairs level of complexity comparison study will be referred as “LOC-study”. In this survey, the selected media of “with-image” was adopted to explain the BRT system prior to both of these SP structures.

4. MEDIA-STUDY SURVEY 4.1 Questionnaire Design The system explanation was made by comparing the existing bus with BRT based on ‘type 1’ BRT from Table 3. Figure 2 shows the system explanation page of questionnaire presented to the respondents before the hypothetical questions (scenarios). As mentioned above, the system (BRT) explanation is made in two different media of with-image and with-out image and the Figure 2 shows the sample version for the media of ‘with-image’. The “without-image” version will be exactly same but without pictures. As Media-study’s main target is to compare the system explanation effect, both the “with-image” and “without image” versions were distributed randomly such that a respondent receives either with-image or without-image version of questionnaire. In this Media-study, the full-set SP technique (where respondents receive questions randomly) was not adopted instead SP with same questions for all respondents were purposely used to compare the pure effect of Media. A SP questionnaire was given with six scenarios and each scenario was having four alternatives. Each alternative with four attributes and maximum attribute levels were set to three. Selected attributes and its level values are as follows: travel time (TT)={15, 20, 30}min, travel time variance (TTV)={0, 5, 10}min, fare (F)={10, 20, 30}Rs (100Rs=1US$), comfort={EBus, BRT}. Each respondent received 6 scenario x 4 alternative question sets and one sample scenario of the SP questionnaire is given below in Figure 3. In order to eliminate intrusion of interviewer’s verbal demonstration (as it may effect respondents’ preference), the drop-and-pick-up survey conduction method was used by giving two weeks time for respondents to complete the questionnaire. Drop-and-pick-up was 1670


conducted by: visiting household in-person; explained the purpose; if respondent accepted explained filling method; dropping questionnaire; finally, collected back in-person.

Figure 2 System explanation comparing Existing Bus and BRT for with image version

Figure 3 One sample scenario of SP from Media-Study questionnaire

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4.2 Media-Study Output and Discussion Overall return rate of 40.7% (285 handed over 116 collected) was observed. This less rate is mainly due to conduction method of drop-and-pick-up method (purposely added to eliminate interviewer interfere on BRT demonstration) and also because users were not so familiar with this survey method. In general, interview method is the most common and a little familiar method to collect data in developing countries. 7% 5% The mode share of regular commuters’ (mainly 2% 14% 21% Car workers) response and the subset of car- 10% M.Bike Car owned-commuters were aggregated in the left P.Bus Service Bus and right side of the Figure 4. It can be seen P.Bus Others that public bus share is high (76%) as this is a Train 76% common phenomena in most of the developing 65% countries. Public bus usage among car owners Car Owned Workers Workers is still high (65%) and is an attractive Figure 4 Mode share of commuters standpoint for the needs of improved transit system.

% of BRT Prefered

The segmental variation has also been considered in the study. However, the conduction method of drop-and-pick-up does not control the user-selection inside the household and therefore respondents’ segment distribution was not spread well across the segments but got concentrated. It has been observed that the income variable was poorly responded (as it exists 100 even in developed countries). Also, the car Without.Imag With.Image IMAGE TEXT ownership is found to be a good interpreter of 80 income. The variation in age segment is 60 illustrated in Figure 5 and it shows the effect 40 of image among all groups, although the 20 effect differs across age segments. Therefore segment variation is important in developing 0 < 30 30 -40 40 - 50 50 -60 > 60 countries. Elderly people’s visual problem got Age(/Yrs) minimized in image case as seen in the Figure Figure 5 BRT preference by Age 5. 9%

9%

more E.Bus

more BRT

Equaly Ans

Scenario

100% E.Bus The answers were aggregated to check the 14% 80% BRT answering behavior (chosen in unique or 60% 40% Not same rhythmic manner) and trade-off behavior 20% No ans (chosen alternative with same mode -mode 0% thout Image Witooth TWi ext Olny preferable answers). The aggregation based on 68% Image Image all selection goes to same mode, not same Figure 6 Answering pattern and Media effect mode, or not at all answered is given in the right side of Figure 6. The higher percentage (68%) of “not same” case says that respondents are not biased to either mode and they have tried to trade-off their options. The right side Non Response rate distribution, in Figure 6, says that the media of E.Bus BRT with and with-image are giving effect on With response and with-image media is superior in Without explain the system to unfamiliar users. With

Without

Non-response rate has also been tested out with considering each category and only two Figure 7 BRT preference and non response rate scenarios shown in Figure 7. Unexpectedly, for Household the image case shows reduced non-response 1672


rate is another interesting output for further studies. By considering Figure 6 (right side) and Figure 7, it could be concluded that for the same information but system explanation media gives considerable influence on preference. Thus it is very important to consider every single change in questionnaire design in the contest of developing countries.

5. LEVEL OF COMPLEXITY (LOC)-STUDY SURVEY 5.1 Questionnaire Design This Level of Complexity study also conducted at the same area in which the media-study was conducted. This also used BRT ‘type 1’ (from Table 3) as case system. Considering the output of Media-study, this LOC-study was planned to be conducted using the selected media of with-image for all respondents. Also, it was planned to adopt paper-based household personal interview surveys rather than drop-and-pick-up conduction. Level of complexity of the hypothetical questions has been planned to test by adopting two different levels of complexity in terms of number of alternatives per choice set: simultaneous-set and sequentialpairs. In case of simultaneous-set, SP questionnaire was having four scenarios and each scenario was having four alternatives. Each alternative was presented with three attributes and at most three attribute levels. Selected attributes and their level values are as given in Table 5. Table 5 Selected attributes for SP and its level values Attributes Mode Attribute levels E.Bus {30, 35, or 40} Travel Time (TT)/(min) BRT {20, 25, or 30} E.Bus {10, 15, or 20} Fare (F) / (Rs = 0.01US$) BRT {20, 25, or 30} Comfort {E.Bus, BRT} Each respondent received 4 scenario x 4 alternative question set for simultaneous-set. A sample scenario from the simultaneous-set is given below in Figure 8. Unlike Media-study, here the simultaneous-set were given randomly to eash respondents, as typical SP survey conduction method. In oder to compare the effect of level of complexity, a scenario, given in the simultaneous-set, was broken down into different pairs and rearranged to the form of sequential-pair of hypothetical question sets, as menthioned above. By considering respondent burden, in terms of questionnaire length, in this LOC-study, only a single scenario has been selected from simultaneous-set and given in sequential-pair form. Therefore, one particular respondent will receive four simultaneous-sets and one sequential-pair, which has rearranged from one of the simultaneous-set scenario. For example, Figure 9 depicts the corresponding sequential-pairs for the simultaneous-set sample given in Figure 8.

Figure 8 One sample scenario of “simultaneous-set” from LOC-study questionnaire

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The LOC-study was conducted in September 2006 using paper-based household personal interview survey. Interview was conducted by: visited household in-person; explained the purpose; if respondent accepted explained filling method; and collected back in-person same time by waiting.

Figure 9 One sample scenario of “Sequential-set” from LOC-study questionnaire

5.2 Level of Complexity (LOC)-Study output and discussion From this household personal interview survey, 188 completed questionnaires were received. Based on the collected sample, the analysis has been made in the following order. Some variable and their values or dummy values used in the analysis in Table 6. Table 6 Selected attributes for SP and its level values Variables Value Sex 0=Male (M) ; 1= Female (F) Age Young= 18 ~ 24; Middle=25~59; Elders=60 ~ Income/(1000Rs) Low= 25 Car ownership (CO) 0= Not owned; 1=Car owned Socio-economic characteristics of the respondents were given in Figure 10. From 10(a), it can be seen that male participation is double compare to female counterpart. It is due to the local culture that generally female response only if man of the household is absent. The same behavior can also seen in age groups. Therefore, reaching all segment groups is difficult in developing countries. 31% of non-response for income field has been observed. As income is minded as sensitive information, people generally use to be reluctant to declare their own income. However, household income data is little better and it can be seen from part (d) of the Figure 10. By observing the vehicle ownership (motor-bike also included) and car ownership

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information, it can be said that most of the household does not own any vehicle and the percentage of ownership may reduce further if motor-bike is excluded. Among car owned household, most of them possess only one car and it may be used by more than one person. This might be also the reason, beside the economic reason mentioned earlier, behind the fact that car owned commuters also uses public buses. Mid 42%

F 31%

M 69%

(a) Sex 9%

7%

High 12%

No Ans 31%

Low 15%

(c) Personal income Mid 29%

Mid

3+ 1%

No 59%

(e) Vehicle ownership

No Ans 20%

Elders

84%

One 35%

One 19%

High 13%

Young

Two 5%

Not Ans 2% No Car 79%

Low 38%

(b) Age

(d) Household income

(f) Car ownership

Figure 10 Socio-economic characters of the respondents (one person per household) The data has been analyzed using binomial logit model for deriving users’ utility functions and therefore for finding significance of the selected attributes. The following utility function was considered in this study and it is given in Equation (1).

U ( EBus) = a1(TT ) + a 2( F )

U ( BRT ) = a1(TT ) + a 2( F ) + C

(1)

Where ai = parameters of the relevant attributes ( i = 1 and 2) C = mode specific constant TT = Travel time (min) F = Fare (SL Rs) When adding additional attributes of socio economic items such as income, car ownership etc then the above mentioned equation is slightly modified as given in Equation (2).

U ( EBus) = a1(T T ) + a 2( F ) U ( BRT) = a1(T T ) + a 2 ( F ) + ai (Vi ) + C

(2)

Where i = 3, 4, 5, ... Vi = selected additional attributes Using the formula given above, the binomial logit analysis has been carried out using GAUSS software. The derived modal for the formation, shown in Equation (1), using basic attributes alone, is given in Table 7. The additional cases were also prepared with different combination of additional attributes of sex, age, income etc. using the formulation stated in Equation (2). But, the attributes of personal information were observed as not much reliable in producing 1675


meaning full model. Therefore few more cases have been made with cross checking attribute like car ownership, household type etc. The car-ownership attribute has shown comparably a good model and is given in Table 8. Table 7 Parameters estimated for basic attributes simultaneous-set (Sim) sequential-pairs (Seq) TT/(min) -0.080 (-4.891) -0.240 (-3.957) Parameters F/(Rs) -0.078 (-3.247) -0.301 (-3.867) (t-test) Constant 1.540 ( 4.267) 1.292 (4.452) -605.81 -101.19 L(0) Statistical -455.64 -81.08 L(β) 2 Parameters 0.248 0.199 Adj.ρ N 293 146 Ratio of (F/TT) 0.975 1.254 Table 8 Parameters estimated for basic attributes plus car ownership simultaneous-set (Sim) sequential-pairs (Seq) TT/(min) -0.084 (-5.026) -0.247 (-4.014) -0.075 (-2.952) -0.310 (-3.907) Parameters F/(Rs) (t-test) CO (1 ~ 0) 1.234 ( 5.218) 0.560 ( 1.244) Constant 1.197 ( 3.152) 1.16 ( 3.777) -605.81 -101.19 L(0) Statistical -438.97 -80.27 L(β) 2 Parameters 0.275 0.206 Adj.ρ N 293 146 Ratio of (F/TT) 0.893 1.255 In both models, the sign of the parameters of all attributes are obtained as expected. The model accuracy measured by Rho-square values (maximum likelihood ratio) are also in the accepted range (0.2 ~ 0.4). The values of “t-test” are also says that the parameters are statistically significant. In order to compare model difference, statistically, BRT preferences were calculated based on utility functions and derived models using actual values of attributes given to each individual, and tabulated in Table 9. The “μ” values represents average BRT preference ratio upon exiting bus. Table 9 BRT preference comparison of modals with some selected example values Eq.1 (Table7) Eq.2 (Table8) Without SEC With Car (car = 1) With Car (car = 0) Sim Seq Sim Seq Sim Seq μ

0.772

0.686

0.773

0.744

0.725

0.664

σ N

0.076

0.167

0.079

0.143

0.088

0.180

874

146

234

39

640

107

Δμ=μ1−μ2 Δσ =

Δμ/Δσ

σ 12 N 1 + σ

2 2

N2

0.086

0.029

0.062

0.014

0.024

0.018

6.134 > 1.96

1.246 < 1.96

3.476 > 1.96

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This comparison clearly shows that the model from simultaneous-set and sequential-pair are statistically differ for the case of general commuters and for non-car-owned commuters but statistically indifference for car-owned commuters. Therefore, it can be said that car-owned commuter’s choice were similar for both complexity (Sem and Seq). Thus, car ownership said to be correlate with literacy in developing countries, and identified as important index. The clear difference in BRT preference across different segments could be seen only from sequential-pair (Seq). It dictates that sequential-pair might be easier in trade-off selection, as it only deals with binary choice per selection though the questionnaire might be lengthy. Overall, the observed preference is not same from these two levels of complexity even though questions were conceptually same.

6. CONCLUSION The segment variations of personal attributes are wider in developing countries and they are essential in grasping total preference. Therefore, this study has designed a survey approach using hypothetical question settings in contest of new transit system implementation in developing countries. The study is mainly focusing on how the questionnaire design will affect user’s preference and how the design could be modified to grasp more reliable data from users. Physical design of questionnaire is considered under two different theme; system explanation ways (Media) and level of question complexity (LOC). The study has observed the basic problem in covering all segment groups into the survey. Due to concentrated response on specific segments and very less response from other segments, introducing segmental variations into the model becomes impossible. Conduction of completely same questionnaire with new transit system explanation in two different Medias of with-image and without-image under hypothetical question setting (Media-Study) shows difference in respondents’ preference. It could be said that the difference due from respondents’ literacy by either inexperience and/or lack of knowledge of completely new transit system (BRT). Pictorial superiority in transferring the information is found in the with-image case and with-image media has been concluded as a better media for demonstrating the new system in questionnaire surveys. Conduction of questionnaire survey to compare two different level of complexity (LOC) in terms of number of alternatives per each choice set (simultaneous-set and sequential-pairs), by giving same number of alternative in different structural form in hypothetical questions, also shows difference in respondents’ preference. It could be said that the difference due to respondents’ literacy by understanding in trade-off questions, where, in the case of simultaneous-set, respondents need to choose from more alternatives (four) and more attributes (three) at the same time. This study identified sequential-pair, where respondents receive pairs of alternatives, can gives more reliable information and suitable for developing countries. Car-ownership has been found as a good index of literacy. Overall the study concludes that conceptually designed same questionnaire reflects considerable difference in users’ response and this difference is not negligible when it comes to the practical scale. Therefore questionnaire design needs more attentiveness on new transit implementation in developing countries. A difference in response has obviously observed but the cause of such difference is still not answered qualitatively. It needs further research considering selected media of with-image 1677


and level of complexity (LOC) of ‘sequential-pair’ question sets. A special consideration has to be made on personal attribute variance for more systematic approach design on new transit system implementation in developing countries contest.

ACKNOWLEDGEMENT The authors would like to express their sincere thanks to International Association of Traffic Safety and Science (IATSS) for funding this study, Prof Amal Gumarage, Transportation laboratory of Moratuwa University, who helped in arranging students for household surveys

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