How can we move commuters from private to public transport? A case study of car and bus modal choices in Johannesburg

One of the main transport policy strategies that government can address to make transport sustainable is to influence private transport users to move from private to public transport. With the high increase in fuel prices over the past year and global warming, sustainable transport, and specifically fuel saving measures, were given new priority by international and local governments. In view of the increased priority locally on sustainable transport, a case study in Johannesburg undertaken to estimate mode choice factors of bus and private transport users in the inner-city areas, is reviewed to assist government on the most significant policy measures they can take to move private transport users to public transport. The study took the form of a stated preference discrete choice study conducted as part of the development of the GTS2000 transport model for Gauteng by the Gauteng Department of Transport, Roads and Public Works. The paper covers the design of the survey and the SP experiments, the main survey results, the calibration results of discrete mode choice models, and sensitivity analysis of the impact of the choice factors on modal split. Finally conclusions are drawn on the most effective and efficient policy measures to achieve a shift in mode choice in favour of public transport. Acknowledgement The Gauteng Department of Public Transport, Roads and Works, is gratefully acknowledged for their support for the project and permission to present this paper. INTRODUCTION One of the main transport policy strategies that government can address to make transport sustainable is to influence private transport users to move from private to public transport. With the high increase in fuel prices over the past few years, sustainable transport, and specifically fuel saving measures, was given new priority by international and local governments. This coincides with the increasing concern internationally on the negative impacts of global warming, which is another motivation to promote public transport over private transport. A major international research study had been undertaken to “develop a more rigorous understanding of the conditions under which the process of growing unsustainable transport demand could be reversed, by changing travelers’, shippers’ and carriers’ behaviour (Rizet, 2008). In South Africa the main debate and focus of planners was on improving public transport mainly to retain public transport captive users. With the increases in incomes of the poor communities over the last decade, coupled with poor public transport, the main trend in travel behaviour was for public transport users to buy cars as soon as they can afford it. Little attention was given to influencing higher income private transport users to make use of public transport. Fortunately, two factors in SA are working together to make significant progress in this regard. These are the priority and funding given by government to invest in modern public transport systems for the 2010 Soccer World Cup and leaving a legacy afterwards, as well as the international sharp increase in fuel prices. Good examples of the modern public transport systems are the Gautrain high-speed train services in Gauteng, and the planned Bus Rapid Transit (BRT) systems in many cities in South Africa. The Gauteng Department of Public Transport, Roads and Works completed the comprehensive recalibration of its strategic transport model (GTS 2000 Model) in 2006 from first principles (Gauteng Department of Roads and Public Works, 2006). One of the main purposes of the re-calibration of the GTS 2000 Model was to give the model a strong public transport capability. The model needs to support the government’s policy to promote and restructure public transport and to serve user needs. The emphasis of current transport legislation, policies and planning, such as the National Land Transport Transitional Act (2000) and Integrated Transport Plans, is on user preferences and meeting user needs. The model therefore needed to have a strong behavioural basis based on user preferences. Discrete choice stated preference (SP) models provided the ideal technique to achieve these objectives. A review of SP mode choice models developed in Gauteng province indicated that a large number of studies have been conducted amongst low-income public transport captive communities(Gauteng Department of Roads and Public Works, 2006, Del Mistro and Arentze, 2002, Van Zyl, Lombard, and Lamprecht, 2001). These model parameters could therefore be transferred to the Gauteng modal split model, which would save time and cost. However, it was realised that there is a gap in the market segments that would be important to address. This was the middle-income market of car users, who have a choice between car and bus. Appropriate strategies of improving bus services to attract users from private transport are regarded as one of the important strategies to test, and which have the best potential to attract car users to public transport. It was therefore decided to conduct a small SP survey amongst car and bus users in order to calibrate a binary modal split model of car and bus mode choice. This paper summarises the SP study that was conducted, with a view to assisting government on the most significant policy measures they can take to move private transport users to public transport (Gauteng Department of Roads and Public Works, 2006) A professional market research company was appointed to conduct SP surveys to obtain information from short-distance car and bus commuters in Johannesburg regarding their choices between car and bus transport. The paper covers the following: • design of the survey and the SP experiments; • the main survey results; • the calibration results of discrete mode choice models; • sensitivity analysis of the impact of the choice factors on modal split; and • finally conclusions are drawn on the most effective and efficient policy measures to achieve a shift in mode choice in favour of public transport; SURVEY DESIGN AND FIELDWORK The objective of the survey was to obtain information from short-distance car and bus commuters in Johannesburg regarding their choices between car and bus transport. The survey was designed to estimate RP and SP mode choice models for the GTS 2000 Model. The sample of the respondents consisted of 200 car and 100 bus users. Table 1 gives the distribution of the sample among different areas, while Table 2 gives the distribution among population groups and genders. Table 1: Distribution of sample among areas AREAS SAMPLED BUS USERS CAR USERS TOTAL Malvern 20 40 60 Kensington 20 40 60 Newlands 19 41 60 Paarlshoop, Homestead Park, Mayfair West, Mayfair 21 39 60 Westbury, Brixton 20 40 60 Total 100 200 300 Table 2: Gender, population group and modal distribution USERS BUS CAR Total 100 200 Population group Black 36 36% 76 38% Coloured 18 18% 66 33% Indian 19 19% 26 13% White 27 27% 32 16% Total 100 100% 200 100% Gender Male 50 50% 107 54% Female 50 50% 93 46% Total 100 100% 200 100% Only those commuters who had a choice of mode and who had recently used car and bus for their trip to work had been included in the survey. Car users were targeted who were in close proximity to the main bus routes to the CBD. All of the respondents were adults, average age of 35 years, who lived in neighbourhoods relatively close to the Central Area of Johannesburg, where they also worked (less than 20 km). The questionnaire elicited socio-economic information from the respondents and their households, and trip information relating to the respondent’s usual mode of travel (either bus or car) as well as alternative mode. The questions on the alternative mode allowed RP models to be calibrated. Attitudinal questions were also included on why the respondent preferred his usual mode of transport, and why he/she did not use the alternative mode more often. Separate questionnaires were designed for bus and car users, although obtaining the same information, but distinguishing between the different contexts of the bus and car users. Up-front screening questions established whether the respondent was employed and whether he was a car or bus user. Only employed bus or car users were interviewed. A pilot survey was first conducted to test the questionnaire and the SP design. Some changes were made to the questionnaire, including adjustment of some SP levels, based on the pilot survey. The survey methodology involved face-to-face interviews of respondents at home in their preferred language. Computer Aided Personal Interviews (CAPI) was used with dynamic data validation. Bus users were recruited at bus stops, while car users were recruited at their homes within walking distance from bus stops. The survey was conducted from 1 to 24 November 2003. SP DESIGN The SP design focussed on testing mainly time and cost variables for the purposes of developing a strategic transport model. In addition, the number of SP choices had to be limited in order to prevent respondent burden. The main objective was to test the preferences of middle-income car commuters when considering the choice between car and bus. The best market for bus among car users was considered to be middle-income suburbs located relatively close to the CBD. The survey therefore targeted this market. The following five variables were selected for testing: • Walk time from home to bus (min.) • Wait time for bus (min.) • In-vehicle travel time (min.) • Travel cost (Rand) – difference between bus fare and car fuel cost • Parking cost per day for car (Rand) Three levels of each variable were tested, yielding a full factorial design of 243 choices. A 16choice fraction was selected, allowing main effects to be tested independently. Variables were described, relative to each respondent’s actual travel times and cost, except for walk and wait time by bus, which were fixed levels. The Computer Aided Personal Interviews (CAPI) allowed the generation o