Independent helmet tests: how the STAR ratings work.

Who runs the ratings

The Virginia Tech Helmet Lab rates bicycle helmets with its STAR system, in collaboration with the Insurance Institute for Highway Safety. IIHS published the first set of ratings with Virginia Tech on 26 June 2018. Virginia Tech's ratings page refers to a "Ratings Update" memorandum dated July 2025, and lets readers filter by road, mountain, urban, multi-sport, full-face and e-bike helmets. We did not record how many helmets the list currently holds.

The method

According to Virginia Tech's ratings page:

• each helmet model goes through 24 impact tests, at 6 locations and two impact energies;
• the tests use a drop tower designed to reproduce a head hitting the ground;
• each impact's concussion risk is worked out from peak linear acceleration and rotational velocity, and weighted by how often a cyclist might experience that kind of impact;
• a lower score means lower estimated concussion risk and earns more stars. Virginia Tech recommends helmets with 4 or 5 stars;
• bicycle scores cannot be compared with the lab's ratings for other sports.

The method paper, by Bland, McNally, Zuby, Mueller and Rowson (Annals of Biomedical Engineering, 2019), describes impacts onto a 45 degree anvil covered in sandpaper, at normal velocities of 3.4 and 5.3 m/s, using a NOCSAE medium headform.

How this differs from the mandatory standard

IIHS set out the difference in 2018. The US CPSC standard, it said, requires only that impact acceleration stay under 300 g, uses drops straight onto the surface, leaves out the rim of the helmet and does not test at forces at the level of concussion. The Virginia Tech and IIHS ratings use angled impacts instead. The CPSC's own description of its tests, with a flat anvil at about 6.2 m/s and hemispherical and curbstone anvils at about 4.8 m/s, is on the helmet standards page.

Europe is moving in a related direction. Escape Collective reported in February 2025 that a coming European standard built on the EN 17950:2024 test method would make rotational impact testing mandatory, but that its thresholds, impact speed and locations were not yet agreed and no in-force date was set.

What the published results showed

The first ratings (IIHS, 2018)

IIHS reported on 26 June 2018 that of the first 30 adult helmets rated:

IIHS said all four five-star helmets used MIPS, and that elongated road helmets generally did better than rounder urban helmets.

The method paper (2019)

Bland and colleagues tested 30 CPSC-certified models from 14 brands. STAR scores ranged from 10.9 to 25.3. Road helmets scored better than urban helmets, and helmets with MIPS scored better than those without.

Reading these findings carefully

• Each finding has a year. The 2018 and 2019 results describe the helmets tested then. Virginia Tech says its list changes as helmets are added, and its ratings page cites a July 2025 update.
• MIPS results are test results, not a maker's claim. The researchers found MIPS-equipped helmets scored better in their tests. What MIPS itself says about its system is the maker's claim, and we did not read the maker's own documents. IIHS described MIPS in 2018 as a low-friction layer that lets the head slide relative to the helmet and reduces rotational forces.
• A score is not a guarantee. Virginia Tech says no helmet can prevent all head injuries. A suspected head injury needs medical care.
• A rating is not a rule. Whether a helmet may be worn in a race depends on the body's rule, set out on the helmet rules in racing page, and whether it may be sold depends on the mandatory standard where it is sold.

The e-bike category

Virginia Tech's filter includes an "e-bike (NTA)" category. That may refer to the Dutch NTA 8776 standard for speed-pedelec helmets, but we did not research that standard and cannot confirm it.