Are side curtain airbags required by law?

In most places, no law explicitly mandates side curtain airbags by name, but several safety regulations effectively make them standard in new passenger vehicles by requiring performance in side impacts and preventing occupant ejection; older vehicles are not required to be retrofitted. Below is a breakdown of what the rules say in the U.S., Canada, Europe, and elsewhere, and what it means for buyers and owners today.

What U.S. law actually requires

Federal rules do not say “you must install side curtain airbags.” Instead, the National Highway Traffic Safety Administration (NHTSA) sets performance standards that most automakers meet with curtain airbags. Two standards are key: FMVSS 214 (side impact and pole test) and FMVSS 226 (ejection mitigation). Together, they have made head-protection curtains commonplace in new light-duty vehicles since the mid‑2010s, though the rules are performance-based and allow alternatives such as advanced laminated glazing.

The following points summarize the relevant U.S. standards and their practical effects:

• FMVSS 214 (Side Impact Protection): Upgraded in a 2007 rulemaking to add an oblique pole side-impact test, phased in from 2011 to 2015. It requires head, thorax, and pelvis protection in side crashes. While it doesn’t prescribe airbags, most manufacturers use torso side airbags and head-protecting curtain airbags to pass.
• FMVSS 226 (Ejection Mitigation): Final rule issued in 2011, phased in from 2013 and fully effective for applicable vehicles by September 2017. It limits occupant ejection through side windows in rollovers and side impacts. The standard doesn’t mandate airbags, but curtain airbags that deploy and stay inflated are the most common compliance method; laminated side glazing is another route.
• Scope and exemptions: These standards generally apply to light vehicles up to 10,000 lb (4,536 kg) GVWR. Certain configurations (e.g., some convertibles or specialty vehicles) may have partial exemptions or alternative compliance pathways.
• Not retroactive: Vehicles built before the phase-in dates are not required to be retrofitted with curtain airbags.
• Enforcement and repairs: Federal law prohibits disabling required safety systems. If a vehicle was originally built with side airbags, they must remain functional for compliance and for resale in many states.

In practical terms, nearly all new U.S. passenger cars, SUVs, and light pickups now include side curtain airbags, but they are a de facto result of performance standards rather than a direct mandate to install them.

Canada: Similar rules, similar results

Canada’s safety regulations largely align with the U.S. and likewise do not specify side curtain airbags by name. Canadian Motor Vehicle Safety Standards (CMVSS), including CMVSS 214 (side impact) and CMVSS 226 (ejection mitigation), impose similar performance requirements and timelines, leading manufacturers to install curtain airbags to achieve compliance across the North American market.

Europe and other regions under UN regulations

European Union law and many countries that adopt United Nations Economic Commission for Europe (UNECE) regulations rely on performance-based crash standards rather than mandating specific equipment like curtain airbags. Two UN regulations are central: UN R95 (side impact) and UN R135 (pole side impact). Neither explicitly requires curtain airbags, but the pole test especially drives head-protection solutions, and curtain airbags are a common response. Consumer ratings (e.g., Euro NCAP) further incentivize head protection, accelerating widespread adoption.

Here are the key regulatory and market drivers outside North America:

• UN R95 (Side Impact Protection): Sets injury criteria in a moving barrier test; does not prescribe airbags.
• UN R135 (Pole Side Impact): Requires performance against a narrow pole impact, pushing manufacturers toward head protection solutions; curtain airbags are prevalent.
• EU General Safety Regulation (GSR2, Regulation (EU) 2019/2144): Mandates a suite of advanced safety features (e.g., AEB, ISA) but does not mandate side curtain airbags specifically.
• NCAP programs (Euro NCAP, ANCAP, Latin NCAP): While not law, their test protocols and star ratings reward head and far-side protection, effectively encouraging curtain and center airbags.

The combined effect of legal tests and market ratings has made curtain airbags commonplace across Europe, Australia, Japan, and many other markets without an explicit statutory mandate.

Older vehicles, used sales, and repairs

Most jurisdictions do not require retrofitting older vehicles with side curtain airbags. However, if a vehicle was originally equipped with airbags, laws generally prohibit removing or disabling them, and repairs after deployment must restore them to working order. Some states or provinces also regulate the sale of vehicles with inoperative airbags and require disclosure or repair prior to sale.

Edge cases and commercial vehicles

Heavy trucks and certain specialty vehicles may fall outside the scope of passenger-vehicle side-impact and ejection-mitigation standards. Additionally, some convertibles or vehicles with unusual window configurations may use alternative compliance approaches (such as reinforced structures or laminated glazing) rather than curtain airbags.

Practical takeaways for buyers and owners

If you’re evaluating safety features or shopping for a vehicle, these points can help you understand what’s included and why:

• New light-duty vehicles: Expect side curtain airbags to be standard in most modern cars and SUVs due to compliance with side-impact and ejection-mitigation performance rules.
• Used vehicles: There’s no requirement to retrofit older models, but if the car originally had side airbags, they should be present and functional. Check for airbag warning lights and repair history.
• Feature verification: Look for “side curtain airbag” markings on the headliner/upper pillars, check the owner’s manual, or consult the VIN build sheet to confirm equipment.
• Glass types: Some vehicles may use laminated side glass as part of ejection-mitigation strategy; this is normal and compliant when properly engineered.
• Resale and inspections: Tampering with airbags is illegal, and many jurisdictions require disclosure or repair of deployed airbags before sale.

Paying attention to these details will help ensure you get the expected level of head protection and remain compliant with safety laws.

Timeline snapshot

The following timeline highlights milestones that influenced the widespread adoption of side curtain airbags without explicitly mandating them:

• 2007: NHTSA issues FMVSS 214 upgrade adding the pole side-impact test (phase-in 2011–2015).
• 2011: NHTSA finalizes FMVSS 226 (ejection mitigation), with phase-in starting 2013 and full compliance by 2017 for applicable light vehicles.
• 2010s: UNECE UN R135 pole test takes hold; Euro NCAP emphasizes head and far-side protection in ratings.
• 2017 onward: Virtually all new U.S. light-duty vehicles include curtain airbags to meet performance standards; similar prevalence across many global markets.

These steps made curtain airbags a de facto standard feature in modern vehicles despite the absence of a direct mandate.

Summary

No major jurisdiction explicitly requires “side curtain airbags” by name. In the U.S. and Canada, performance standards for side-impact protection and ejection mitigation strongly incentivize their use, and most new light-duty vehicles have them. Europe and other regions follow performance-based UN regulations and consumer test protocols that likewise drive adoption. Older vehicles are not required to be retrofitted, but disabling originally equipped airbags is illegal, and repairs must restore functionality.