EPA's survey of in-use driving patterns: Implications for mobile source emission inventories

The paper presents EPA's preliminary findings on the in-use driving behavior and vehicle emissions. EPA contracted for several large-scale studies of in-use driving patterns in order to assess the adequacy of the driving cycle used in the current FTP. The driving behavior characteristics covered here are: start time, start driving, and speed and acceleration not represented in the current FTP. Two additional factors, air conditioning and road grade, are examined for their potential emission impact. Following this introduction, the paper is divided into five sections. This is followed by a discussion of EPA's cycle development efforts. The third section discusses the vehicle emission assessment based on the results of the test program. The last section summarizes the preliminary implications for current emission inventories.