Are collapsible bicycle helmets as protective against head injuries as conventional designs?

William Dawber, Claire E Baker, Xiancheng Yu, Mazdak Ghajari

Accident Analysis & Prevention, 2026

Abstract

Collapsible (foldable) bicycle helmets are marketed as a lightweight, portable alternative to conventional helmets, but it is unknown whether their protective performance matches that of conventional designs. We present the first study to compare the two helmet types, testing 30 helmets — 24 conventional models and all six collapsible models sold in the UK — at four impact locations. Average predicted linear injury risk was higher for collapsible helmets than for conventional ones (24% vs 20%), with no significant difference in rotational injury protection. Collapsible helmets were on average substantially heavier than conventional helmets, and this added weight was associated with higher injury risk. Rotational-protection technology such as MIPS was far less common among collapsible helmets (1 of 6) than conventional helmets (12 of 24); a collapsible model fitted with MIPS ranked 2nd of 30 overall, while the same model without it ranked 26th. All helmets tested met minimum UK and European safety standards. Our findings suggest that, while individual collapsible helmets can perform well, the category as a whole currently offers lower average protection than conventional helmets, and we recommend wider adoption of rotational-protection technology in collapsible designs.

Cite as (BibTeX)

@article{dawber-2026-are-collapsible-bicycle,
  title={Are collapsible bicycle helmets as protective against head injuries as conventional designs?},
  author={William Dawber and Claire E Baker and Xiancheng Yu and Mazdak Ghajari},
  journal={Accident Analysis & Prevention},
  volume={239},
  pages={108814},
  year={2026},
  doi={10.1016/j.aap.2026.108814}
}