[6月4日]能源经济学workshop 讲座时间：6月4日（星期四）上午10:30-11:30 讲座地点：国家发展研究院万众楼大教室 主讲人：  Clifford Winston (Brookings Institution 美国布鲁金斯学会)   Title: The effet of road congestion on consumers’ vehicle size choice: implications for safety and emissions Abstract: U.S. consumers have responded to technological improvements in automobile engines during the past three decades by purchasing cars with significantly greater horsepower.  A possible explanation of this preference for greater power and, accordingly, greater vehicle size is the significant growth in congestion over time; that is, motorists who frequently travel in congested conditions may feel safer and more comfortable in larger more powerful vehicles than they do in smaller less powerful vehicles. However, the increase in vehicle size caused by congestion is likely to have adverse consequences for motorists’ safety for two reasons: (1) The frequency of multiple vehicle accidents increases with traffic volume and congestion; and (2) In a two-vehicle accident involving a large and small vehicle, the larger vehicle protects its occupants at the cost of occupants’ safety in the smaller vehicle.  In addition the increase in vehicle sizes increases fuel consumption and emissions. The purpose of this research is to develop a dynamic disaggregate model to quantify the effect of congestion on vehicle-size choice and to measure the implications of this positive relationship for motorists’ safety and fuel consumption.  The model is estimated using data on Seattle motorists’ vehicle-size choices and their actual commutes, which enable us to determine the congestion and travel delays that they experience. The results of this study will identify a neglected and additional benefit of policies that can reduce highway congestion by quantifying the reduction in automobile injuries, fatalities, and fuel consumption from a change in the distribution of vehicles sizes on the road that reflects a reduction in the share of larger vehicles.