An important source of anthropogenic greenhouse gas (GHG) emissions is the air transport sector, which accounts for approximately 2% of global GHG emissions. Therefore, reducing GHG emissions from aircrafts has become a major challenge for transportation authorities worldwide. In recent years, much research has focused on tax ideas related to the CO₂ emissions produced by air transport, such as the voluntary carbon offset (VCO). This study investigates the willingness of economy class air passengers to pay to compensate for the CO₂ emissions produced during their journeys from Taiwan to Hong Kong. Together with the Spike model, a framework known as the contingent valuation (CV) method offers a way to investigate how much the air passenger would be willing to pay to offset a journey’s airplane-generated CO₂ emissions. The Spike model was applied to address the problem of zero willingness to pay (WTP). The results obtained in this study are consistent with the results found in previous studies and therefore can provide valuable insights into pricing strategies for airlines.

This paper investigates the relationship between medical treatment costs and the length of hospital stays resulting from motorcycle crashes involving the elderly. The World Health Organization defines ‘elderly’ as people more than 65 years old. The sample for this study consisted of data for the year 2007 collected by the Bureau of National Health Insurance, Taiwan. We develop models for predicting medical costs and the length of hospital stays based on diagnosis, hospital and user types. The seemingly unrelated regression equation (SURE) model was applied first to investigate the relationship between medical costs and the length of hospital stays. The SURE model shows that the type of injury (e.g. head injury) is statistically significant and has positive effects on medical costs for motorcycle crashes involving the elderly in Taiwan. Due to the statistical insignificance of the dependency between medical costs and length of hospital stays, two separate simple linear regression models were subsequently estimated. For motorcycle crashes, patients over 80 years old had the highest medical costs. The findings reinforce the need for transportation authorities to focus on preventing certain types of injuries that are particularly serious and costly for the elderly in Taiwan.