The DOT does not test helmets before they hit the market. Instead, manufacturers self-certify that their products meet the FMVSS 218 standard .
The criteria used for DOT testing were established in the 1970s and are often criticized for allowing unacceptably high impact forces (up to 400Gs). How to Spot a "Fake" or Unsafe DOT Helmet Are Motorcycle Helmet Standards Reliable? DOT HELMETS
Between 2014 and 2019, independent labs contracted by the NHTSA found that 72 out of 167 tested helmets failed to meet performance standards. The DOT does not test helmets before they hit the market
The certification is the minimum legal safety standard for motorcycle helmets in the United States. However, reports and independent testing suggest a significant gap between "legal" and "safe," with some studies showing a failure rate as high as 43% during government spot checks . The DOT Certification Crisis How to Spot a "Fake" or Unsafe DOT