California Air Resources Board (CARB)CFD Testing

Get your aero devices tested by the Team that sets the standard in CFD modeling of Trucks

Having decades of experience in applying Computational Fluid Dynamics (CFD) to determine the aerodynamic performance of automotive vehicles and trucks, for brands like Honda or NASCAR, and as active members of the professional body that sets the industry standards, we are able to apply our expertise to conduct CFD testing on trucks or aero devices to ensure they meet greenhouse gas (GHG) emissions standards.


As of 2019, changes to the California Air Resources Board (CARB) Tractor-Trailer Greenhouse Gas (TTGHG) Interim Aero Device Approval Program allows use of Computational Fluid Dynamics (CFD) to measure the CdA of your aero devices instead of only allowing wind-tunnel or coast down testing.

TotalSim has extensive physical testing and wind tunnel testing experience and we have found that, in most cases CFD can be the most cost effective and efficient method for CARB certification. We can provide advice based on your specific design needs as to whether wind tunnel or other physical testing might still be appropriate. Contact us to discuss your specific situation.


TotalSim’s Experience

Our own Co-founder and Technical Director, Naethan Eagles, serves on the Society of Automotive Engineers (SAE) Committee and has helped shape the CFD testing procedures the trucking industry has adopted.

We have helped clients gain CARB certification through our CFD testing method and our in-depth understanding allows us to guide you efficiently and effectively through the process too.


Testable Devices, but not limited to:

  • Trailer Skirts
  • Trailer Tails
  • Tractor-Trailer Gap
  • Underbody of Trailer
  • Mudflaps*

*Note: Some devices, including certain mudflaps, can only be accurately certified through the CFD method or coast down tests because reducing the size of these devices to fit on a scaled wind tunnel model can fail to capture the physics properly, leading to poor drag assessment.

CFD Testing Process

Our CFD testing methodology is approved by CARB and is in accordance with the SAE J2966 testing method. Learn more about our simple and effective process below:

Step One

Send us your geometry. Your device will be modeled with a Standard Class 8 Tractor and a 53 ft. Trailer that meets the CARB geometry requirements. It will be simulated in accordance with CARB CFD Protocols and the SAE J2966 CFD testing procedure.

Step Two

If your device successfully surpasses the CdA improvement threshold, TotalSim will incorporate the data (including any images and any supporting documents) into the CARB Interim Approval Request Form for Aero Drag Reduction Technologies – needed when a manufacturer formally requests approval of a new device.

Step Three

You will then submit the Interim Approval Request Form for Aero Drag Reduction Technologies to CARB for certification approval. During the review, TotalSim will work directly with CARB on the CFD data portion of the submitted application if needed.


Fixed Price: $9,500
Our fixed pricing cost, includes the following

  • Testing of a single device using the approved CFD testing method
  • Generating and tabulating CFD data and images
  • Incorporating required information into the CARB Application

Don’t have CAD? We can draw geometry for a small additional fee.


Get certified! Complete this form to get started.


Not ready for CARB testing or looking to improve your device? Visit our Commercial Vehicle page to see how we can help.

"*" indicates required fields

Contact us below to get started on your certification

Not ready for CARB testing or looking to improve your device? Visit our Commercial Vehicle page to see how we can help.

Related Solution

Scroll to Top