Greenhouse Gas Emissions Due to Shift to Light Trucks in the United States, 2000-2047

There has been a dramatic market shift away from passenger cars and towards light trucks, particularly sport utility vehicles (SUVs), in the United States (U.S.). Beginning with model year (MY) 2012, light trucks now make up the majority of new light duty vehicles (LDVs). This study quantifies the total impact of the rise of light trucks from MY2000-2017. Using data on vehicle production and greenhouse gas (GHG) emissions (in grams per mile) from the U.S. Environmental Protection Agency's 2018 Automotive Trends Report, I estimated total emissions from passenger vehicles in the U.S. from 2000-2017. I then constructed alternate vehicle fleets based upon the shares of passenger cars, SUVs, vans, and pickup trucks during MY1980 and MY1996. Furthermore, I broke the MY1980 and MY1996 scenarios into two: a Fixed scenario, in which the MY1980 and MY1996 fleet breakdowns remain constant from 2000-2017, and a Tech Change scenario, in which the total share of passenger cars and light trucks remained constant, but the relatives shares of Car SUVs, Truck SUVs, vans, and pickups was allowed to float to reflect real world dynamics. I also constructed a third alternate vehicle fleet, using data on the shares of these vehicle types in the European Union during that period; those data came from the International Council on Clean Transportation "European Vehicle Market Statistics" for 2018-2019. I then completed this same analysis through the end of these vehicles' projected functional lives, which will span from 2030-2047. Based upon my analysis, these additional light trucks will produce anywhere from 867-3,519 million short tons of carbon dioxide equivalent (MTCO2e) across their lifetimes, offsetting 19-75% of the projected emissions savings from the MY2011-2025 CAFE standards. Combined, the social cost of these additional emissions and the increased risk of traffic fatalities may reach $94.3-350.7 billion. The "GHG Emissions by Scenario" folder contains the individual emissions calculations for each of the five separate scenarios (MY1980 Fixed, MY1980 Tech Change, MY1996 Fixed, MY1996 Tech Change, and EU). The "SUV Scenarios Combined" spreadsheet collects all of these results and includes an analysis of the social cost of these additional GHG emissions. The "Fuel Economy by Vehicle Type Scenarios" spreadsheet incorporates the U.S. EPA data I utilized and includes various calculations and analyses of it that formed the basis for this research.

美国汽车市场已出现显著转型，乘用车市场份额持续向轻型卡车转移，其中尤以运动型多用途汽车（Sport Utility Vehicle, SUV）最为突出。自2012款车型年（Model Year, MY）起，轻型卡车已占据美国轻型载货汽车（Light Duty Vehicle, LDV）新车市场的多数份额。本研究量化了2000至2017款车型年间轻型卡车崛起带来的整体影响。
本研究依托美国环境保护署（U.S. Environmental Protection Agency, EPA）2018年发布的《汽车趋势报告》中的车辆生产与温室气体（Greenhouse Gas, GHG）排放数据（单位：克每英里），估算了2000至2017年间美国乘用车的总排放量。随后，本研究基于1980款与1996款车型年的乘用车、SUV、厢式车与皮卡的市场份额占比，构建了多组替代车队情景。
进一步将1980款与1996款车型年的情景拆分为两类：其一为固定情景，即2000至2017年间1980款与1996款车型年的车队结构始终保持不变；其二为技术变革情景，即乘用车与轻型卡车的总市场份额保持恒定，但乘用车、SUV、厢式车与皮卡的相对份额可浮动，以反映真实市场的动态变化。此外，本研究还依托国际清洁运输委员会（International Council on Clean Transportation, ICCT）2018-2019年发布的《欧洲车辆市场统计》中的欧盟同期各车型类型份额数据，构建了第三类替代车队情景。
随后，本研究针对这些车辆的预计全生命周期（覆盖2030至2047年）完成了相同的分析流程。分析结果表明，上述新增轻型卡车在其全生命周期内将产生867至3519百万吨二氧化碳当量（million short tons of carbon dioxide equivalent, MTCO2e）的排放量，抵消了2011至2025款车型年企业平均燃油经济性（Corporate Average Fuel Economy, CAFE）标准预计减排量的19%至75%。综合来看，这些额外排放所带来的社会成本，叠加交通事故死亡风险上升所造成的损失，总额可达943亿至3507亿美元。
「各情景温室气体排放量」文件夹包含了五类独立情景（1980款车型年固定情景、1980款车型年技术变革情景、1996款车型年固定情景、1996款车型年技术变革情景以及欧盟情景）的单车辆排放量计算结果。「SUV情景汇总」电子表格整合了上述所有结果，并包含了针对这些额外温室气体排放的社会成本分析内容。「不同车型类型情景燃油经济性」电子表格纳入了本研究使用的美国EPA数据，并包含了支撑本研究的各类相关计算与分析工作。