The top tether is one of the most effective — and most ignored — safety features for forward-facing car seats. NHTSA-funded research found the top tether reduces forward head movement by an average of 4–6 inches in crash testing. At crash speeds, that distance is the difference between a child's head clearing the back of the front seat or striking it at significant velocity.
In a frontal crash, a forward-facing car seat wants to rotate forward at the base, pivoting the top of the seat — and your child's head — toward the back of the front seat or the dashboard. The top tether is a strap that connects from the top of the car seat to a dedicated anchor point in the vehicle, preventing this rotation. Without it, even a correctly installed LATCH-connected seat will allow substantially more forward head excursion.
All passenger vehicles sold in the US since 2000 are required to have tether anchors in the rear seating positions. The location varies by vehicle type:
After installing the seat with LATCH or the seatbelt, route the tether strap over the top of the seatback (remove the headrest if necessary to route correctly), clip it to the anchor, and tighten until there is no slack. The tether should be taut, not just connected. After tightening, try to push the top of the seat toward the vehicle front — it should move minimally.
Use the top tether regardless of whether you installed with LATCH or the vehicle seatbelt. The tether is a separate third connection point that works with both installation methods. Many parents assume LATCH alone is sufficient — it is not. LATCH secures the base; the tether controls the top. Both matter.
Most rear-facing infant and convertible seats do not use a top tether in the rear-facing position. In rear-facing mode, the back of the shell is against the vehicle seat and already limits movement. Check your specific seat's manual — a small number of convertible seats do allow tether use rear-facing, but most manufacturers instruct against it as it can affect the seat's crash performance angle.
Important: This article is for general education. Always follow your car seat manual and vehicle owner's manual. For personalized installation help, contact a certified Child Passenger Safety Technician (CPST) or find an inspection station at nhtsa.gov.
SafeCarCompare shows injury margins from NHTSA crash-test data — beyond star ratings. Enter any two vehicles to see head, chest, and neck injury margins side by side.