The National Highway Traffic Safety Administration has proposed two hardware changes to its THOR-50M crash test dummy, the adult-male-sized dummy the agency is working to write into federal regulations. One is a 3D-printed face insert made of thermoplastic polyurethane. The other is a spine that locks into four positions: erect, neutral, slouched and super slouched.
The proposal appeared in the Federal Register on September 22 as a supplemental notice of proposed rulemaking, and public comments are due October 22. Neither change is mandatory. Both are offered as options, and the agency says manufacturers that already own original-spine dummies would not need to upgrade.
Two optional parts, one dummy
According to the Federal Register notice, published under Docket No. NHTSA-2023-0031 for 49 CFR Part 572, the agency proposes to specify “the Humanetics four-position spine as a permitted optional” configuration alongside the original spine. The spine can be set in only four positions, which NHTSA says makes it easier to adjust and easier to fit with the in-dummy data acquisition systems that manufacturers prefer. Testing found “equivalence between the original spine and the four-position spine within expected test-to-test variation.”
The face insert is proposed “as an alternative to the face foam.” The foam part requires a 24-hour recovery period after each impact before the dummy can be used again. The printed insert removes that wait, and the notice says testing showed “improved repeatability and reproducibility” compared with the foam, along with better durability. For a test lab running many crashes back to back, a face that is ready immediately saves scheduling time, and the better repeatability means results from one test to the next should scatter less.
A dummy years in the rulemaking pipeline
The THOR-50M has been in the rulemaking pipeline for years. NHTSA first proposed incorporating it into Part 572 in a notice published September 7, 2023, and the 2026 document follows a supplemental notice from July 9, 2024. According to the new notice, the changes respond to industry comments asking for alignment with European testing practice while keeping safety equivalence. The four-position spine matches what the notice calls Euro NCAP TB026, the European consumer-testing technical bulletin.
The agency did not adopt every European practice. NHTSA says it is keeping its own face impact qualification test rather than moving to Euro NCAP’s visual inspection, because an “objective method to check the system response” remains necessary. The proposal also carries a deregulatory label: NHTSA describes it as an Executive Order 14192 deregulatory action and expects savings from international harmonization.
The THOR-50M and the frontal ratings
The notice describes the THOR-50M as an adult male of roughly average height and weight for use in frontal crash tests. In an interim report to Congress on crash test dummies, NHTSA said the dummy offers “improved biofidelity” in the thorax, shoulder, spine, knee-thigh-hip, lower leg and abdomen, and can take multi-point deflection measurements in the thorax and abdomen that the older Hybrid III cannot. The same report says the Hybrid III 50th percentile dummy entered the federal regulations in 1986, and that possible uses for the THOR include frontal NCAP tests.
That last point matters for anyone reading this as a change to star ratings. The 2023 proposal states that the New Car Assessment Program “evaluates vehicle performance in a frontal crash test at 35 mph using a belted HIII-50M dummy.” Defining the THOR in Part 572, the same document says, “will enable its use in regulatory and consumer information programs.” The 2026 notice adds the dummy to the regulations and, in its words, imposes no requirement to use it. No published NHTSA source reviewed for this article moves the frontal ratings to the THOR.
An NHTSA presentation comparing the two dummies in frontal crash tests states that vehicles currently tested in the United States “have been optimized with the HIII-50M,” and that “use of THOR-50M should drive future restraint optimization, hence reduced injury values and future occupant safety,” in an agency presentation on THOR-50M frontal tests. The presentation also notes that the THOR-50M sits slightly higher and further rearward than the Hybrid III, with a head-to-wall measurement of 664 millimeters against 639, and that it is judged more biofidelic even where some thorax readings run higher. Humanetics, which makes the four-position spine and sells the dummy, says on its company perspectives page that “Euro NCAP and ANCAP (Australia) have placed THOR into their 2020 protocols.”
What comes next
Comments on Docket NHTSA-2023-0031 close October 22, 23 days after publication. Technical questions go to Garry Brock at NHTSA and legal questions to John Piazza, both at 202-366-1810. After the comment period, the agency would have to issue a final rule before the printed face insert or the four-position spine became part of the regulated dummy, and it has not said when.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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