IIHS Check Fit Booster Ratings and the Britax Frontier 90


Considering buying a Britax Frontier 90 or Pinnacle 90 Harness-2-Booster seat?  Maybe you already bought one, based on our reviews or because they appeared on our recommended seats list?  Perhaps you have recently seen or heard that the IIHS did not give your carseat a “Best Best” or “Good Bet” rating and you are now wondering if it is safe to use?  Don’t Panic!  “Check Fit” does NOT mean “Unsafe”!

So what does a “Check Fit” rating from the IIHS mean?  Quite simply, it means you have to check how well the booster fits your own child, in your own vehicle.  Install the booster in your vehicle, buckle and route the seat belt, all according to the instructions in the owner’s manual.  Ideally, the lap belt should be fairly flat on the upper thigh, not up on the tummy.  The shoulder belt should be centered on the shoulder; it should not be falling off the shoulder or rest on the child’s neck.  What if it doesn’t fit well?  Keep using it for now to keep your child safe and read on for some suggestions to improve the safety for your child!  For more on booster fit, please see CarseatBlog’s coverage of the 2013 IIHS Booster Ratings.

The first important thing to note is that the new 2013 IIHS Booster Ratings are not results of dynamic crash tests.  Second, they do not consider ease-of-use or additional safety features at all.  The evaluations are only measurements of seatbelt fit to an average 4 to 8 year-old child using these seats in booster mode in a few vehicle seating scenarios.  Finally, these ratings DO NOT apply at all if you are using these or any other combination booster seat in the 5-point harness mode.  In regard to harness use, CarseatBlog agrees with the American Academy of Pediatrics, “All children whose weight or height is above the forward-facing limit for their [5-point harness] Child Safety Seat should use a belt-positioning booster seat until the vehicle lap-and-shoulder seat belt fits properly, typically when they have reached 4 feet 9 inches in height and are between 8 and 12 years of age. There is a safety advantage for young children to remain in Child Safety Seats with a harness for as long as possible before transitioning to booster seats.”

How does the IIHS know if a booster will fit your child and vehicle?  Good question!  They evaluate booster fit on a standard dummy, representative of a typical 6-year old child, measured in four scenarios that mimic real vehicle use.   What if your child is a different size than the dummy or you have a vehicle that varies significantly from any of their test scenarios?  That could mean the booster fits somewhat better or worse than the rating suggests, but overall the ratings should still provide meaningful comparisons.  CarseatBlog recommends that parents consult the IIHS Booster Ratings, as they are a great place to start and generally reflect a range of children and vehicles.  We do caution that their evaluations do not always apply directly to every possible combination of child and vehicle.  That means that a model that earned a “Best Bet” may not fit ideally with your child and vehicle.  Similarly, a model that earned a “Check Fit” rating may provide a good fit for your child, in your particular vehicle.

So, a lower rating does not necessarily mean your child is less safe, unless you check yourself and find the belt fit to be marginal or poor in booster mode, of course.  For example, I found the seatbelt fit of a Britax Frontier 90 (“Check Fit” rating) in booster mode to be very reasonable on my 8-year old child in a couple of popular vehicles, a Toyota Highlander and Prius.


As mentioned in the video, it is worthwhile to note that the Britax Frontier 90 and Pinnacle 90 have among the highest seated torso height limits for the 5-point harness system of any combination harness/booster carseat.  That means most kids can use the harness until they are 8 years old or possibly even older.  That is a very safe option if you did happen to find that the seatbelt did not fit your child well in booster mode, especially on younger or less mature children who may benefit most from the extra points of restraint in a 5-point harness system.

secureguard frontier90 priusAnother option for the Britax combination seats is the availability of the SecureGuard accessory clip, shown to the right on a child in a Toyota Prius.  This can not only improve the fit of the lap belt in a static measurement like the one done by the IIHS, but it also provides an extra point of restraint.  That can help keep the child from moving under the lap belt in an actual crash and therefore keep that lap belt from moving into the tummy as well.  That’s something unique to Britax and was not evaluated in the IIHS booster mode ratings for the Frontier 90 or Pinnacle 90.  Current owners using the new Britax combination carseats in booster mode should contact Britax to inquire about obtaining a Secure Guard clip, or one can be purchased from Amazon for under $18.

The previous Britax combination seat, the Frontier 85, was a “Best Bet” in booster mode.  We have comparison photos between the Pinnacle 90 (left) and Frontier 85 (right).  Both fit well on an older child in an Acura MDX:

Britax Pinnacle 90 belt fit  Britax Frontier 85 belt fit

Below is an example comparison of the Pioneer 70 (left) and Frontier 85 SICT (right) in a Honda Odyssey, on a smaller, 4-year old child, who would otherwise be using the 5-point harness mode.  You can see the fit is a little better on the Frontier 85.  For smaller kids, especially those closer to the booster minimum requirements, the 5-point harness mode is the preferable alternative for a marginal booster mode lap belt fit.  Another seating position or use of the Britax SecureGuard Clip accessory may improve lap belt fit if the booster mode must be used instead of harness mode for some reason.

Pioneer 1  Frontier 1

Please note that the Britax Pioneer 70 Combination seat has somewhat lower harness height and weight limits than the other models, but is still comparable to most combination models and should fit many kids in harness mode to 6 years or more.  For more specifics, please check out our review of the Pioneer 70Frontier 90 and Pinnacle 90.  The IIHS evaluations indicate that the lap belt fit did not meet the test criteria on their dummy in two of their four simulated vehicle scenarios, resulting in a “Check Fit” rating for these models.

So, in summary, the “Check Fit” rating is simply advice to do your own evaluation of belt fit.   This applies to other models as well.    Many kids, especially older ones, will still fit safely in the lap and shoulder belts when using these carseats in booster mode.  If your child does not get a good lap belt fit, you do have a few options.

  1. First, if possible, continue using the 5-point harness mode if your child is within the weight and height limits listed in the owners manual.  The IIHS ratings DO NOT apply to 5-point harness mode use.
  2. Second, try a different seating position!  If the lap belt doesn’t fit well in the center seat, it might fit better on an outside seat, or vice versa.  If not, maybe it will work well in another vehicle where your child rides.
  3. Third, for Britax models, contact Britax and request the accessory Secure Guard Clip, as it may improve the lap belt fit and add to the child’s safety in a crash by providing a 4th point of restraint on a Britax booster or combination harness/booster model.
  4. Finally, if nothing else helps, you may need to find another booster that does work well with your child and vehicle.  Perhaps you can use your current booster in another vehicle where it does fit acceptably and start with our Recommended Boosters and IIHS Best Bets to find a replacement.  Keep using the booster you have until you find a new one, even if the fit isn’t ideal!


Finally, here is the Britax response to the 2013 IIHS Booster Ratings:

In its November 2013 report, the Insurance Institute for Highway Safety (IIHS) ranked the PARKWAY SG and PARKWAY SGL as “BEST BETs” in high-back booster mode. IIHS also recommended parents confirm proper positioning (i.e., “Check Fit”) for lap and shoulder belts when using the booster mode of BRITAX’s FRONTIER 90, PINNACLE 90 and PIONEER 70 Harness-2-Booster seats in certain conditions. In harness mode, these three seats properly fit nearly all vehicles and children. When a child is transitioned to booster mode – before he or she outgrows forward-facing harness mode – the lap belt may not fit low and tight across a child’s upper thighs without the use of the BRITAX SecureGuard accessory clip.

The IIHS report evaluates how adult lap and shoulder belts from a wide variety of vehicles fit booster seats from a variety of manufacturers. The assessment is not a crash test.  Rather, IIHS measures how a vehicle’s three-point lap and shoulder belt fits an average child-sized dummy seated in a booster.

“Our uncompromising commitment to safety, reflected in the ongoing enhancements of our products, has made BRITAX a name trusted by millions of parents and caregivers throughout the world,” said Jon Chamberlain, president of BRITAX.  “BRITAX products undergo the most rigorous testing in the industry and we work closely with child passenger safety technicians, child safety advocates and vehicle manufacturers to ensure all BRITAX seats can be properly installed and used correctly each and every time.”

BRITAX will implement a slight change on the FRONTIER 90, PINNACLE 90 and PIONEER 70 by January 2014 that will be designed to address the occasional instance where proper belt fit is not achieved.


Harness-2-Booster Seat Best Practices

BRITAX recommends parents secure children using a five-point harness as long as possible. A child should transition from harness to booster mode only when he or she outgrows the seated shoulder height limit and/or weight capacity.

BRITAX offers a full line of infant/child and combination Harness-2-Booster seats with some of the highest top harness slots in the industry. However, when a child is ready for booster mode, BRITAX recommends parents use the following guidelines to ensure the booster seat and vehicle seat belt are properly positioned:

  • The lap belt should fit low and tight across the child’s upper thighs, not the soft abdomen.
  • The shoulder belt should fit snugly across the child’s mid-chest and shoulder. The vehicle belt should NOT be positioned over the child’s neck, under the child’s arm or behind the child’s back.
  • Either the booster seat or the vehicle head restraint should be adjusted properly for the child’s height.


BRITAX encourages parents to call representatives at its Consumer Services department at 1-888-427-4829 or visit a local car seat checking station with any concerns regarding the fit or installation of any child car seat at any time.


We focused on the Britax combination seats because they were specifically highlighted in the IIHS press release and Status Report, presumably because they did not earn a “Best Bet” rating like their predecessor, the Frontier 85.  Britax will apparently be offering owners of the Frontier 90, Pinnacle 90 and Pioneer 70 a Secure Guard Clip as their child is moving to booster mode use.  Britax is also working with the IIHS to make a small update to the design to improve its rating.  This change could appear within a few months.  So current owners can get a good lap belt fit using Secure Guard and early next year a small update should be available.  Either way, current and future owners should get a good fit with a wide variety of vehicles and children.

Checking the fit of ANY booster is a good idea, regardless of the manufacturer or rating!  With the exception of the Secure Guard clip, that may only be used on the Britax combination seats and boosters, some of the other suggestions here may apply to other combination models that also received a “Check Fit” rating.  You may find additional information on the Britax USA and IIHS websites.


One Response

  1. Jennifer February 1, 2016