Specifically, the purpose of this study is to address two questions that are pertinent to the issue of the interrelationship between congestion growth, employment growth, and income growth. First, we focus on the how congestion growth affects income growth and employment growth. Second, we investigate the opposite case, namely, how income growth and employment growth affect congestion growth. To this end, we evaluate 86 US metropolitan areas by utilizing a simultaneous equation model. This study is expected to provide important empirical evidence to obtain a better understanding of the interaction between traffic congestion, employment, and income in an urban area.
The next section presents the analytical framework focusing on the simultaneous relationship between employment, income, and congestion. In the section 3, we describe the measurement of congestion and data. Then we provide empirical findings. In the last section, we discuss our results and suggest transportation policy implications.
2. Analytical Framework: A Simultaneous Equations Model of Employment, Income, and …show more content…
Average delay hours per commuter in a year has increased since the 1980s. Particularly, it grew by almost 30 hours between 1982 and 2005. These trends, of course, are associated with rapid urbanization in the U.S. However, delay per commuter decreased between 2005 and 2011. Notably, after 2005, the highest point of delay per commuter has decreased, while the lowest point of delay per commuter has increased. This is likely because many U.S. metropolitan areas have experienced different growth patterns during the period. For example, congestion levels in large metro areas that have undergone severe traffic congestion may decrease, whereas congestion levels in medium-sized metro areas may increase during the periods. Hence, there may be a difference of the relationship of economic components and congestion between 1990s and 2000s. In order to understand the relationship of congestion and economic growth in a different economic conditions (economic boom in 1990s vs. economic recession during 2000s), analysis separated by the two time periods would be much helpful. In this regard, we focus on the period of 1990s and 2000s in this study, which is expected to show a recent trend as well as past trend of the interplay between economic components and congestion. We will discuss it in-depth in the next