Q & A: New Side-Impact Rule, FMVSS 213a

This article originated in the July/August 2022 issue of Safe Ride News.

On August 1, NHTSA amended FMVSS 213 to require CRs to meet a dynamic side-impact test. This final rule, added as FMVSS 213a, fulfills a mandate from Congress and is much like NHTSA’s 2014 Notice of Proposed Rulemaking on this topic. Below are the answers to some basic questions CPSTs may have about this new rule.

This front view of the Side Impact Seat Assembly, or SISA, is figure 2C from the new FMVSS 213a rule.

Q: When does this rule go into effect?

A: Manufacturers have until June 30, 2025, to comply with the new requirements. Early compliance is optional.

Q: How will the test be done?

A: The new test simulates the vehicle acceleration and intruding door of a real vehicle-to-vehicle side-impact crash (a “T-bone”) at 19 miles (30.5 km) per hour. A specific test seat (called SISA, or Side Impact Seat Assembly, shown in the drawing below) was designed to be like a rear seat with the tested CR in an outboard position, near a simulated vehicle door. The test replicates a near-side (closest to the child) impact into the door of a vehicle. The test setup is slightly angled so that the CR experiences the type of loading commonly seen in real side-impact crashes.

Q: What CRs will be tested?

A: Any CR made for a child who weighs up to 40 pounds or is up to 43.3 inches tall will be required to pass the new side-impact test. This includes testing of rear-facing and forward-facing CRs (and of both modes, when CRs offer both). RF-only CRs with a base will be subject to the requirements when used with the base only. (Through its own testing, NHTSA found that RF-only CRs that passed side-impact tests with a base also passed without the base and, therefore, has opted to not subject manufacturers to additional testing of these CRs in baseless mode.)

Q: How will tested CRs be installed?

A: The NPRM proposed to test CRs only when installed using LATCH; however, after reviewing comments, NHTSA was convinced that there was a safety need to also test CRs when installed using a lap-shoulder belt. The final rule requires tests using both installation methods. Forward-facing CRs should be installed with the tether attached when one is present (though no other systems, such as load legs, should be deployed).

Boosters are not specified in the final rule, but any booster made for use by a child who weighs less than 40 pounds or is shorter than 43.3 inches would be subject to testing under the standard. (In recent years, all boosters and CRs in booster mode have moved to a minimum child weight of 40 pounds or more; only a few of the 135+ booster models on the 2022 Product Listing at state a minimum weight limit of 30 pounds, and even those have been updated to 40 pounds since the list was posted.)

Q: Which crash test dummies will be used?

A: The tests will use the existing 1-year-old CRABI dummy to test CRs for use by children weighing 11 to 30 pounds. For CRs for children weighing more than 30 pounds and up to 40 pounds, NHTSA created the instrumented Q3s 3-year-old dummy. Developed many years ago specifically for side-impact testing, the Q3s was approved in a September 2020 final rule. (Note: The NPRM had proposed a 22-pound cutoff to determine which of the dummies to use. However, that would have required testing most of today’s RF-only CRs using the far-too-tall Q3s, which NHTSA now says is unrealistic and out of alignment with real-world usage. So, for the final rule, 30 pounds was set as the cutoff.)

Q: How will the standard require CRs to perform?

A: The side-impact standard will require CRs to restrain the crash test dummy (or dummies), manage crash forces, and prevent harmful head contact with structures. When testing with the Q3s, the CR must also limit crash forces on the dummy’s chest. In addition to these performance measures, the CRs will be assessed post-crash to ensure they meet the existing FMVSS 213 test requirements for system integrity, contactable surfaces, and buckle release.

Q: Why does the test apply only to CRs for use by children under 40 pounds?

A: The test is limited because NHTSA has determined that no test dummy larger than the Q3s would provide reliable test measurements, and the agency does not want to create a test that purports to simulate larger children but, in actuality, would be meaningless. NHTSA notes that the design elements required for CR models to pass at 40 pounds will also protect larger children who continue to use those models (as most models in FF mode can nowadays be used to a child weight of 65 pounds).

Q: Why does the test simulate a near-side impact?

A: NHTSA data shows near-side impacts to be more injurious than far-side impacts for children under age 4, accounting for 80% of moderate-to-critical injuries to restrained 0- to 3-year-old children involved in side impacts. Most of these injuries are caused by contact with the interior surface of the vehicle—usually an intruding door—which the new testing will replicate. By comparison, far-side impacts account for fewer injuries to young children, and the impact surfaces vary considerably, so these surfaces would be difficult to replicate in a standardized test.

Q: What does this testing requirement mean for CR manufacturers?

A: On one hand, new test requirements mean extra time, effort, and expense when bringing new CRs to market. On the other hand, manufacturers have been preparing for this development for many years. The NPRM was issued eight years ago, and even at that time, the topic had already been discussed for over a decade. While, in the ensuing years, manufacturers have taken varying approaches to their own voluntary side-impact testing, they also had ample warning of the testing NHTSA would require in this final rule, and NHTSA has stated that many current models are likely to pass the new requirement. Therefore, in many ways, the financial impact of this rule has already been absorbed by CR companies.

Since many companies have been voluntarily testing models using other side-impact approaches (such as those used in Europe or Australia), they will now need to decide whether or not to continue using those tests. Many will likely shift to testing U.S. models by following the U.S. requirements only.

Q: What does this testing mean for CRs?

A: Because energy-absorbing side structures, like deep side wings and pods, can provide protection for children in side impacts, more of these features will likely be included in future CR designs. While these features are already present on many CR models, having been added voluntarily by manufacturers, some of the more basic models on the market may see future upgrades.

The prospect of side-impact testing also caused some concern that future CR designs would have to become wider (limiting installation options) and/or heavier (limiting portability) in order to pass testing. In response to comments expressing these concerns, NHTSA used various methods to test these hypotheses, and it states these concerns are meritless. The agency concluded that a CR would neither need to be wider nor made heavier in order to pass the new side-impact test, provided it’s properly engineered.

The new testing requirement may also lead to changes in instructions for use. For instance, given the 30-pound cutoff for using the Q3s dummy for testing, it seems likely that, in the future, fewer RF-only models will be sold that state a maximum child weight limit of more than 30 pounds.