Bicycle helmets sold in the US are all required to meet one mandatory federal standard — but what that standard actually tests for changed in a meaningful way in 2026.
Linear vs. rotational impact
For decades, mandatory helmet standards — CPSC in the US, EN 1078 in Europe — tested almost exclusively for linear impact: how well a helmet absorbs a straight-on hit. Real crashes are often angled rather than straight-on, and an angled impact against pavement can cause the head to twist or rotate rapidly, which is a separate injury mechanism (linked to concussions and more serious brain injuries) that pure linear-impact testing doesn't directly measure.
In 2026, the mandatory US CPSC standard was updated to add angular acceleration testing for the first time, measuring how much a helmet allows the head to rotate during an angled impact, not just how well it cushions a direct hit. This is a genuinely significant change, not a minor revision — it's the first time rotational protection has been part of the baseline mandatory requirement rather than an optional extra.
MIPS is a technology, not a certification
You'll see "MIPS" (and similar systems like WaveCel or SPIN) prominently marketed on many helmets. It's worth understanding what this actually is: MIPS is a licensed component — a low-friction liner inside the helmet that lets the shell rotate slightly relative to the head during an angled impact — not a certification or safety standard in its own right. No testing body "certifies a helmet to MIPS." A helmet either meets the mandatory CPSC standard or it doesn't; MIPS and similar systems are one way manufacturers help meet or exceed rotational protection requirements, not a separate stamp of approval layered on top.
Independent ratings go beyond the minimum
Virginia Tech's helmet testing lab publishes an independent, widely respected star rating system that evaluates both linear and rotational performance, going beyond simply confirming a helmet meets the mandatory minimum. Checking a specific helmet's Virginia Tech rating, where available, gives a more detailed picture of real comparative performance than certification alone can.
The one thing people forget
A helmet should sit level on the head, about two finger-widths above the eyebrows, with the straps forming a "V" shape under each ear and about one finger-width of space between the chin strap and chin — no rocking side to side or front to back once buckled. And replace a helmet after any real crash impact, or any visible damage to the shell or foam, regardless of how new it is; the protective foam is generally designed to absorb serious impact only once.