The general equilibrium effects of high-occupancy vehicle lanes on congestion,sprawl, energy use,and carbon emissions

High-occupancy vehicle (HOV) lanes have been promoted to encourage carpools, reduce traffic congestion, and improve air quality. At the partial equilibrium level, commuting with three workers per automobile clearly reduces highway congestion, lowers carbon emissions, and saves energy compared with three single drivers. This paper develops a numerical urban simulation model to generate the general equilibrium effects of HOV lanes on urban spatial structure, energy use, and greenhouse gas emissions. The major findings are that while HOV lanes reduce traffic congestion and improve welfare, the fall in transportation cost leads to urban sprawl, which results in higher dwelling energy use and a larger carbon footprint. Overall, the HOV lane policy has little effect on total energy consumption and carbon emissions. This is another classic case of general equilibrium effects reversing the partial equilibrium effects of an urban policy. In contrast, a gasoline tax policy leads to less urban sprawl but is less effective at lowering energy consumption and carbon emissions. Imposing congestion tolls is a more effective tool at reducing traffic congestion, saving energy, and lowering carbon emissions.     

新中国成立初期的上海里弄整顿

新中国成立初期,作为基层社会管理体制支撑的居民委员会出现了三大危机:组织衰败、劣化、蜕化问题。为此,中国共产党在基层里弄中发动了一场规模宏大的清理整顿工作。在这次整顿工作中,政府通过赋予街居组织以体制支撑,造就了街居组织对非单位人的有效控制;通过对干部、群众的双重清理,传统基层统治权威代表较为彻底地从基层社会权力空间中退出,居民的认同也转向新的街居组织。至此,居委会的效能获得全面提升,政府与居民之间的政治沟通不畅问题迎刃而解,而居委会也因此焕发了生机。     

Dynamic road pricing and the value of time and reliability

High Occupancy Toll (HOT) lanes that use dynamic pricing to manage congestion and generate revenue are increasingly popular. In this paper, we estimate the behavioral response of drivers to dynamic pricing in an HOT lane. The challenge in estimation lies in the simultaneity of price and demand: the structure of dynamic tolling ensures that prices increase as more drivers enter the HOT lane. Prior research has found that higher prices in HOT lanes increase usage. We find that after controlling for simultaneity HOT drivers instead respond to tolls in a manner consistent with economic theory. The average response to a 10 percent increase in the toll is a 1.6 percent reduction in usage. Drivers primarily value travel reliability over time savings, although there is heterogeneity in the relative values of time and reliability based on time of day and destination to or from work. The results highlight the importance of both controlling for simultaneity when estimating demand for dynamically priced toll roads and treating HOT lanes with dynamic prices as a differentiated product with bundled attributes.