Buick 2006 LaCrosse Owner's Manual page 49

The top tether anchors are located under the trim
covers on the rear seatback filler panel. Flip open the
trim cover to access the anchors. Be sure to use
an anchor located on the same side of the vehicle as
the seating position where the child restraint will
be placed.
Do not secure a child restraint in the right front
passenger's position if a national or local law requires
that the top tether be attached, or if the instructions that
come with the child restraint say that the top tether
must be attached. There is no place to attach the top
tether in this position.
Accident statistics show that children are safer if they
are restrained in the rear rather than the front seat.
See Where to Put the Restraint on page 1-38 for
additional information.
1-43