A USDOT University Transportation Center

Change in Vehicle Emissions 

A change in vehicle emissions refers to any variation in the quantity of gases discharged by a vehicle’s exhaust system. The vehicle emissions that are expelled from the exhaust of an internal combustion engine include nitrogen oxides, particulates, sulfur oxide, hydrocarbons, and carbon monoxide.1 This metric measures the concentration of these gases, many of which are responsible for the changes in climate.2

This indicator helps determine the effectiveness of the following objectives

  • Less Contamination
  • Less Emissions
  • Less Traffic Noise
  • Connectivity and Inclusion
  • Healthy Destinations
  • Less Traffic Violence
  • Active Transportation
  • Green Space

Data Collection

Data on changes in vehicle emissions can be collated using the Motor Vehicle Emission Simulator (MOVES). Additionally, official documentation may be used to offer data on vehicle emissions (brochures or specifications). Vehicle emission data is also easily accessible owing to the European Automobile Manufacturers Association (ACEA).3

Examples

A decade of on-road emissions measurements

The research was conducted by Bishop and Stedman (2008) to ascertain the changes in the emissions produced by different vehicles. Chicago, Illinois, Denver, Colorado, Los Angeles, California, Phoenix, and Arizona were selected as the locations for the research. The researchers could estimate the amount of emissions released from these automobiles. The findings of the study revealed a decrease in carbon monoxide (CO), hydrocarbons (HC), and nitric oxide emissions at every location (NO). Denver had a 56% to a 71% decline in CO emissions, Denver a 27% to a 63% drop in HC emissions, and West Los Angeles a 48% to a 68% drop in NO emissions.

https://www.semanticscholar.org/paper/A-decade-of-on-road-emissions-measurements.-Bishop-Stedman/56c00da6965c4f60039bb7d63e90a46bd8447049

1. Mikulčić, H., Klemeš, J.J., Vujanović, M., Urbaniec, K., Duić, N. Reducing greenhouse gases emissions by fostering the deployment of alternative raw materials and energy sources in the cleaner cement manufacturing process. J Clean Prod [Internet]. 2016 [cited 2022 Jul 13];136:119–32. Available from: https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions
2. Lane, B. Types and impact of vehicle emissions - Air quality car emissions - Tailpipe CO2 [Internet]. Nextgreencar.com. [cited 2022 Jul 13]. Available from: https://www.nextgreencar.com/emissions/types-impact/
3. Estimated U.S. average vehicle emissions rates per vehicle by vehicle type using gasoline and diesel [Internet]. Bts.gov. [cited 2022 Jul 29]. Available from: https://www.bts.gov/content/estimated-national-average-vehicle-emissions-rates-vehicle-vehicle-type-using-gasoline-and