This thesis investigates the determinants of car and motorcycle ownership and use in a city-region which has the dual characteristics of being situated in a developing economy but also having very high car and motorcycle dependence. The rise of car and motorcycle ownership in Sarawak, a state in Malaysia, has caused severe congestion as well as environmental and accessibility issues, particularly in urban areas. Inadequate access to public transport plays an important role in this high dependency. This case study investigates some of the important gaps in the literature relating to car and motorcycle ownership. Firstly, it is commonly assumed that those with lower income tend to purchase motorcycles, while those with higher income tend to own cars. Hence, both types of vehicle are usually considered as substitutes for each other. In the case of Sarawak, however, the simultaneous rise of car and motorcycle ownership challenges this perspective on the interdependency. Secondly, the demand for private vehicle ownership and use is typically investigated using socio-economic and built-environment factors. There are limited studies on the role of human psychological factors towards private vehicle ownership and use, especially with respect to motorcycles. Moreover, most studies have been conducted in the context of the developed world. Understanding the interrelationships between the variables is of significant importance to policymakers to effectively strategize their key initiatives as well as to ensure that the policies are suitable with respect to the context and nature of the population of interest.
A two-part approach incorporating aggregate and disaggregate data analysis is used. First, an aggregate approach using a vector error correction model (VECM) is applied to investigate the determinants of car and motorcycle ownership using time series data at the state level. Second, a disaggregated model is developed by applying partial least squares-structural equation modelling (PLS-SEM) using cross-sectional urban household data. For this purpose, a travel behaviour survey is conducted on a sample of 688 urban households in Sarawak, allowing not only socio-economic and built-environment factors to be obtained, but also a large number of psychological determinants to be gathered. The latter were based on the theory of planned behaviour (TPB) and the norm activation model (NAM), based on which social norms, perceived behavioural control, attitudes and pro-environmental motives were measured. Aside from these factors, the study also explored the interdependency between car and motorcycle ownership as well as the relationships between ownership and use between these two modes.
Based on the aggregate modelling, the VECM analysis showed that gross domestic product (GDP), fuel price and level of employment are significant determinants of car and motorcycle ownership. The findings revealed that as the standard of living rises, both car and motorcycle demand increases. At the state aggregate level, it is found that there is a substitution relationship between both modes. This indicates that, people are highly likely to shift from motorcycle ownership to car ownership in the long-run. For the disaggregate modelling, the PLS-SEM analysis outcomes are separated into four main sub-models, which are (1) the car ownership sub-model, indicating that the socio-economic, pro-environment and social norms factors are significant determining factors, (2) the motorcycle ownership sub-model, indicating that the socio-economic, built-environment, attitude towards transport policy and pro-environment factors are significant determining factors, (3) the car use sub-model, indicating the car ownership, socio-economic and attitude towards transport policy factors are significant determining factors, and (4) the motorcycle use sub-model, indicating the motorcycle ownership, distance to city centre and attitude towards transport policy factors are significant determining factors. The findings highlight the importance of psychological factors as the determinants of ownership and use alongside socio-economic and built-environment factors, although the most important attitudinal factors are attitudes towards transport policy and, in opposition, environmental motives and social norms. In contrary with the state aggregate model, the disaggregate model found a complementary relationship between car and motorcycle ownership, which shows that both demands grow together rather than being alternatives to each other. This may be due to the important functionalities of both cars and motorcycles in the households, which serve other purposes than commuting. Based on the findings, the policy implications in the study include encouraging shifts to other modes of transport through public transport reforms (e.g. buses) in urban Sarawak as well as providing incentives for more environmentally friendly vehicle usage (such as electric cars and motorcycles) through taxes and toll charge exemptions, considering the high level of car dependency.
