2003 Buick Century Owner's Manual - Page 30

To make the belt shorter, pull its free end as shown until the belt is snug. Buckle, position and release it the same way as the f part o a lap-shoulder belt. If the belt isn't long enough, see Safety Belt Extender on page 1-29. Make sure the release button on the buckle is positicmed so you would be able to unbuckle the safety belt quickly if you ever had to. 1-23