Travel behavior change and mechanism of modal shift in Tanzania: a case study of Industrial and office Workers in Dar es Salaam City

Dar es Salaam is one of the developing country cities where the economy is steadily growing and the car ownership is relatively low. However the rate of increase of car ownership and use grows rapidly which results to congestion. As a result of increasing problems of traffic congestion, accidents, inadequate parking space and air pollution. This study investigated mechanisms that can trigger a modal shift from one mode to another in Dar es Salaam. It examined the existing conditions that apply in the use of public transport, non-motorized transport and private cars. It also establishes the primary factors and travel behavior change leading to switch from public and non-motorized transport modes to private cars in Dar es Salaam city. In this particular study, qualitative mobility biography and retrospective survey data collection methods were used in order to study travel behavior over extended period of time. The survey was done in November 2010 and September to November 2011 with the sample size of 1500. Life history calendar recall aid was used to enhance memory recall to improve the reliability of the data. The data were categorized into factors and conditions of mode preferred, that is, the factors and conditions of mode that influenced people to prefer public transport or non-motorized transport and private cars and those which would make people not to prefer a particular mode. Basing on triggers of mode shift, a modal shift model was developed to show the effect such triggers referred as key events, socio economic and demographic characteristics on modal shift. The factors found to effect the mode choice were key events in commuters’ life domains, including change of employment, change of residence and or co-habiting partnership. The mode choice was also affected by socio-economic and demographic factors such as household income, car ownership, age and level of education. Conditions of mode that affected public transport mode choice were reliability, comfort, safety, cleanliness, time efficiency, crews’ behavior and noise.