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Ask a CPST: I Have Three Car Seats, Is It Safe to Travel 3-Across?

Ask a CPST: I Have Three Car Seats, Is It Safe to Travel 3-Across?

Car Seats
As the brand behind the original 3-across car seat, we’re here to answer your 3-across concerns with our resident CPST, Scott.

Riding 1-2-3 isn’t always as easy as A-B-C, but if you’re planning to travel 3-across then we’re here to ensure it’s a safe and secure journey for your Very Important Passengers.


First, please note that not all vehicles accommodate 3-across travel. Before installing any car seat in your vehicle, check the vehicle owner’s manual for approved seating positions as there are some exceptions.

Car seat installation starts with two things: the car seat manual and the vehicle owner’s manual. Every single time. There are no exceptions on this one. Your car seat manual will explain correct installation as per the manufacturer’s guidelines. Your vehicle manual will explain things such as where to locate your lower LATCH anchors, airbags, top tether anchors and whether car seat bracing is allowed. These are the two most important tools in your arsenal with car seat safety!

If your vehicle owner’s manual indicates that you can install car seats in any of the three rear seating positions, great news! But there’s still a few more details to consider for a correct, secure, and safe journey.

Following each of the steps outlined here will mean that it’s safe to travel 3-across.

  • Car seats with a harness, whether rear-facing or forward-facing, must be independently secure and installed as per the instructions in your car seat manual.
  • It is recommended that forward-facing car seats be installed with a top tether.
    In fact, some manufacturers, like Diono, require that forward-facing car seats are installed with a top tether.
  • Each seat should be installed with either the LATCH connectors or the seat belt. Never use both unless specifically allowed in the car seat manual.
  • Then, check each seat at the belt path. If it moves less than 1 inch side-to-side or front-to-back, it’s secure.
  • Seats should not interfere with the space occupied by each independently. This is important to note for center seating positions, as they are often more narrow than the driver and passenger side.
  • If using a booster seat or adult seat belt, the seat belt must be accessible.
  • Infant seats with a base must be securely attached to the base without interference from seats on either side. If you find that either adjacent seat obstructs your ability to securely connect the carrier to the base, this is not correct or safe.

For even more safety tips and advice, head to Scott’s Safety Hub where you’ll find a whole collection of car seat safety demonstrations with our Resident CPST from rear-facing, harness strap safety, headrest positioning and more!

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