Cristian Poliziani | Lawrence Berkeley National Laboratory

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Presentation Description

Medium- and Heavy-Duty (MHD) trucks account for 23% of energy consumption within the U.S. and are major contributors to air pollution. To understand the air pollution contributions from MHD trucks and assess the effectiveness of various policy levers, accurate emission inventories need to be estimated from state-of-art emission models using accurate and representative model inputs. Among those, the fleet composition is one of the most important inputs and has a substantial impact on output emission inventory. However, the on-road fleet composition is often challenging to obtain, especially for the MHD commercial vehicle fleet. The main challenges include (1) the long-haul trucks often move nationally and cannot be sufficiently captured using local data, and (2) the lack of representative truck fleet data with detailed vehicle specifications needed to support emission modeling (e.g., short-haul vs. long-haul, availability of idling technologies). Therefore, in practice, default fleet distributions from regulatory emission tools are often used in combination with local data to fill in gaps, while some critical vehicle attributes such as mileage accumulation rate in those emission models are outdated and not representative.

The recently released 2021 US Vehicle Inventory and Use Survey (VIUS) fills a critical gap in understanding MHD truck fleet distributions and usage at the national scale and can be a great source to update the truck fleet distribution in emission models, especially for long-haul movements. This study aims to understand the latest fleet composition and operational characteristics using 2021 VIUS data and calibrate the fleet composition inputs in regulatory emission models to assess the potential emission impacts of fleet distribution defined using 2021 VIUS and other data sources. Specifically, the 2021 US VIUS data are useful resources to define the short-haul versus long-haul fraction, the vehicle mileage accumulation rate across model years, usage of alternative fuel and powertrain, and the fraction of auxiliary power units for long-haul combination trucks. U.S. EPA’s MOtor Vehicle Emission Simulator (MOVES) will be used to provide emission rates for MHD vehicles and default fleet composition to compare to. The output energy consumption, greenhouse gas emissions, and critical air pollutants (PM2.5, NOx, CO, VOC, HC, etc.) will be compared by applying default fleet distribution versus fleet composition calibrated by 2021 VIUS as inputs. The results from this study will provide the latest insights into U.S. MHD fleet characteristics and the implications of those characteristics on emissions and air quality.

Speaker Biography

Co-presenters

Hung-Chia Yang
Lawrence Berkeley

Haitam Laarabi
Lawrence Berkeley National Laboratory

Alicia Birky
National Renewable National Laboratory

Kyungsoo Jeong
National Renewable Energy Laboratory

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