Using the Canadian postal code system as an example, the top level's binding concept is the postal district, and consists of 18 objects (letters). The next level down is the zone, where the objects are the digits 0â9. This is an example of an overlapping hierarchy, because each of these 10 objects has 18 parents.
The refreshed 2014 Buick Regal GS can now be had with all-wheel drive, though the added grip does come at the expense of a few horsepower. We already sampled the 2014 Regal GS and walked away mostly impressed, but now itâs time to verify how the sedanâs powertrain changes affect its performance numbers.
Buick also has the distinction of being the first automobile maker in the world to equip its cars with overhead valve engines, which it did starting in 1904. In 2015, Buick sold 1,231,941 vehicles, a record for the brand. The main market is in China, where 80% of Buick-branded automobiles are sold. Buicks are also sold in the United States, Canada, and Mexico.