Wednesday, April 7, 2010

Answers to "Mistake Monday" 4/5/10

ANSWERS: (please see bottom of page for teaching points on LATCH)

  • The lower anchor belt & vehicle shoulder/lap belt are BOTH used
  • The lower anchor belt is used in the center seat - in a vehicle which only has the lower anchors for the two side seating positions in the back seat
  • The vehicle's shoulder/lap belt is routed UNDER (instead of over) the metal LATCH bar. 
 Image: Forward-facing Britax Boulevard with vehicle's shoulder/lap belt & top tether
  • When using a lap belt (no shoulder belt), the lap belt gets routed UNDER the LATCH bar on the Britax Marathon/Boulevard/Advocate.
  • The shoulder belt WAS properly routed through the built in locking clip - but it was not shown in this picture since the appropriate locking clip is on the opposite side of the seat.  For forward-facing, use ONLY the built in locking clip that is on the side opposite to where the vehicle's seat belt buckles in.  
  • There is no need for a metal locking clip with this installation because 1. the Britax Boulevard has a built in locking clip for forward-facing which must be used with a shoulder belt installation and 2. this vehicle is post-1996 and therefore has a way to keep the shoulder belt locked for the car seat (in this case a switchable retractor)
  • LATCH stands for Lower Anchors and Tethers for CHildren. It's also known as ISOFIX in Europe and LUAS (Lower Universal Anchorage System) in Canada.
  • LATCH is a way to secure a child safety seat to the vehicle using straps from the child safety seat that connect to special metal anchors in the vehicle.
Vehicles since model year 2003 must have lower anchors in at least TWO positions and tether anchors in at least THREE positions. This means that in most vehicles, the side seats have lower anchors AND tether anchors, while the center seat has a tether anchor but NO lower anchors.  See below for info on the few vehicles that do have lower anchors for the center seat.

    •  LOWER ANCHORS: Lower anchors are a pair of metal “u-shaped” bars hidden in the vehicle’s seat cushion (where the part you sit on meets the part that your back rests on).
    • TETHER ANCHOR: A tether anchor is a metal ring found behind (or sometimes under) the vehicle seat.
This picture shows a typical back seat with the 2 pairs of lower anchors - one for each of the side seats.  The standard spacing between the lower anchors is 11 inches.  Note how the spacing between the inner most anchors is wider than 11 inches.  
***The middle in this picture - and in most vehicles - is NOT a position that has the lower anchors.

This diagram shows how variable the location for the top tether can be - always check the vehicle owners manual for details. 
    • LOWER ANCHOR STRAP: All child safety seats that use the vehicle’s lower anchors have a lower anchor strap with a hook on either end. Some child safety seats have two separate lower anchor straps, each with a hook on one end. These hooks connect to the vehicle’s lower anchors.
    • TETHER STRAP: All forward-facing child safety seats that use LATCH come with not only a lower anchor strap, but also a tether strap. The tether strap comes from the top of the car seat and has a hook on the end that lets it connect to the tether anchor in the vehicle. 
An Analogy - Lower Anchor Strap:Vehicle Seat Belt as Contacts:Glasses
Lower anchors are used INSTEAD of the vehicle's safety belt to secure the child safety seat to the vehicle.  Just like you wouldn't wear contacts and glasses on the same day - as you would see worse rather than better - so too you don't want to use the lower anchors AND the vehicle's seat belt to secure the car seat.  Choose one or the other, as appropriate for the seating position where you are installing the car seat.

Note: in the future there may be a child safety seat that allows for both the lower anchors and vehicle's seat belt to be used at the same time, but currently none allow for this or recommend it.

It's ALWAYS BETTER WITH A TETHER (Forward-facing that is)
Tethers are used IN ADDITION to the lower anchors OR the vehicle's safety belt to secure a forward-facing child safety seat to the vehicle.  Tethers keep a child's brain and spinal cord much safer by decreasing how far the head moves forward - typically by 4-8 inches - which can mean the difference between the child's head hitting something hard or not.

This picture shows a real crash test (using dummies) - where one seat was installed with a top tether and one without.  Notice how the dummy's head moves 6 inches farther forward when the top tether isn't used!

Which vehicles have lower anchors for the CENTER seat?
Stay tuned - I'm off to the NY Auto Show today and will update this portion soon. 

Most common LATCH mistakes:
  1. Child safety seat is installed too loosely
  2. Tether not used on a forward-facing car seat
  3. "Borrowing" the inner most lower anchors from the two side seats to secure a car seat in the center (as was shown in this week's mistake monday picture)
  4. The lower anchor strap is not routed through the correct path on the car seat - for example, the strap may be routed through the rear-facing belt path when the seat is forward-facing.


  1. Would you please tell me why it is important not to barrow an anchor from the side when the seat is in the middle! I would love a like! maybe that will help me drive the problem/answer home!

  2. Clay - I wish I had a better answer than "because it wasn't tested that way" - but right now this is the best answer the vehicle manufacturers are giving. As far as the car seat manufacturers, some feel like their seats won't perform as well with anchors that are more widely spaced than the standard.

  3. I'm sure you've posted this before, but can you please make a post using that top tether comparison pic on facebook? I would like to repost it so all my friends can see it. I've been looking for a pic just like that!