Public transportation policy plays a significant role in facilitating ridership as well as travel modes, economic activities, and environmental aspects. Seoul has experienced rapid urbanization. Also, high density developments and uncontrolled land use gave rise to extensive urban sprawl in the Seoul Metropolitan Areas (SMA). Due to increased use of private vehicles, which created serious traffic congestion, the Seoul Metropolitan Government (SMG) has reformed public transportation policies-introduced bus transportation reform (BTR) in 2004 and reformed fare and ticketing structures in 2009. This research focuses on the relationships between socioeconomic characteristics and commuting patterns by applying smart card data that includes individual travel behaviors during commuting periods. Among regression results, average commuting times are significantly associated with the proportion of population with lower levels of education and the number of public transit stations. These results appear to support the idea that the lower educated people in each district tend to have longer commuting times. Also, the greater availability of public transit stations contributes to shorter commuting times. Finally, analyzing commuting times seems to be important for determining demographic movement as well as locational advantages in certain regions of Seoul based on public transportation policies.

This dissertation is composed of three essays examining adoption of agricultural technologies in Ecuador and intergenerational mobility in the United States. The first essay entitled 'Does IPM Have Staying Power? Revisiting a Potato-producing Area Years After Formal Training Ended' examines (Integrated Pest Management) IPM spread and adoption several years after formal intensive IPM outreach efforts ceased in a potato-producing region in Ecuador. It describes adoption patterns and sources of IPM knowledge in 2012 and compares them with patterns that existed when outreach ceased in 2003. Results show that IPM adoption continues in the area but with a lower proportion of farmers adopting all practices and a higher proportion adopting low to moderate levels compared to 2003. Farmer-to-farmer spread has supplanted formal training and outreach mechanisms. IPM adoption significantly lowers pesticide use and saves production costs for adopters. The second essay entitled 'Can Text Messages Improve Agricultural Outreach in Ecuador?' seeks to understand how receipt of text messages complements training from a farmer field day. It measures the effect of text message receipt on adoption of (Integrated Crop Management) ICM technologies and knowledge about these technologies. In the first part of the paper, we present a theory of behavioral change and its application to adoption of agricultural technologies. In the second part, we use intention to treat (ITT) and an improved-ITT analyses to measure the impact of the intervention. The results of this essay suggest that as providers of information, text messages have some knowledge building effect leading to the adoption of IPM practices. As reminders, text messages effectively increase adoption of IPM practices, in particular recommended pesticides. The third essay entitled 'Determinants of Absolute Upward Income Mobility: The Hidden Cost of Commuting' focuses on commuting times as a determinant of upward income mobility in the United States. We provide an explanation of the channel through which the effect of commuting times on upward income mobility operates. Additionally, it evaluates empirically the effect of commuting on upward income mobility. The empirical results confirm the theoretical model predictions that commuting times affect negatively upward income mobility. / Ph. D.