A USDOT University Transportation Center

Engine Noise and Changes Due to EVs

Engine noise and other changes due to electric vehicles can be used as an indicator to measure traffic noise strategy effectiveness. Most electric cars often emit less traffic noise than commonly used internal combustion engine vehicles.1 This is because electric motors do not need mechanical valves, gears, or fans like conventional combustion engines. EV passengers may only hear the wind and tires while commuting.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

A sound level meter, which can be placed near the vehicle, can be used to measure on-road noise levels. Other options are to use microphones placed inside the car or sensors placed on the vehicle itself to measure the vibrations caused by engine noise. Whichever method is used, it is important to ensure that the data collected is accurate and reliable.3,4

Examples

Measurement of noise from electrical vehicles and internal combustion engine vehicles under urban driving conditions

Research by the Institute of Transport Economics and the Norwegian Centre for Transport Research revealed that at low speeds, electric cars are 4 to 5 decibels quieter than those powered by internal combustion engines. This is because internal combustion engines are significantly noisier than electric ones. Additionally, since electric vehicles do not produce exhaust fumes, there is also less air pollution.

https://www.toi.no/getfile.php/1340825-1434373783/mmarkiv/Forside%202015/compett-foredrag/Lykke%20-Silent%20Urban%20Driving.pdf

1. Krishnan, S. ELECTRIC VEHICLE WARNING SOUNDS: Electric cars are not ultra-silent! [Internet]. Getelectricvehicle.com. [cited 2022 Aug 9]. Available from: https://getelectricvehicle.com/electric-vehicle-warning-sounds/
2. Kuchta, D.M. Quietest cars: Do electric cars make any sound? [Internet]. Treehugger. 2021 [cited 2022 Aug 9]. Available from: https://www.treehugger.com/do-electric-cars-make-noise-5205280
3. What Is A Sound Level Meter? [Internet]. Bksv.com. [cited 2022 Aug 17]. Available from: https://www.bksv.com/en/knowledge/blog/sound/what-is-a-sound-level-meter
4. Vehicle vibration diagnosis [Internet]. Auto Service World. 2011 [cited 2022 Aug 17]. Available from: https://www.autoserviceworld.com/carsmagazine/vehicle-vibration-diagnosis/