Impacts of improvements in rural roads on household income through the enhancement of market accessibility in rural areas of Cambodia

Rural areas in low-income countries often face severe poverty typically caused by insufficient accessibility to basic facilities. Improvements in rural roads are expected to reduce poverty although the mechanism has not been investigated sufficiently. This study empirically analyzes the impacts of rural road improvements implemented from 2012 to 2014 in Cambodia, highlighting local residents’ accessibility to local markets. This study assumes two causal relationships: rural road improvements have upgraded the accessibility and travel frequency to local markets, and the upgraded accessibility and travel frequency to local markets have led to a growth in local residents’ income. The hypotheses are statistically tested with a dataset developed through a questionnaire survey conducted in three areas in 2016. The dataset contains responses from 400 local residents to questions concerning their social attributes, livelihoods, travel modes, travel frequency, and time/cost of travels to the basic facilities. The quasi-experimental design incorporating a difference-in-differences design and an inverse possibility of treatment weighting approach revealed that the improvements in rural roads did not affect travel time nor travel cost but significantly enhanced travel frequency to local markets, and that an increase in the travel frequency to local markets and travel time savings significantly contributed to the households’ income growth. The results suggest that the improvement of seasonal reliability in accessing local markets through an introduction of all-weather roads could be critical to enhance household income, particularly in areas where agriculture is a leading industry and weather conditions are unstable across seasons.