The part of I-25 in Colorado passes just east of the Front Range of the Rocky Mountains. That stretch was involved in a large-scale renovation named the Transportation Expansion Project (TRansportation EXpansion) in Denver, and the COSMIX (Colorado Springs Metropolitan Interstate Expansion). These projects and others in New Mexico were necessary because these stretches of I-25 were originally inadequately designed and constructed (the pavement was deteriorating rapidly), and also because urban areas like Albuquerque, Colorado Springs, and Denver had tripled and quadrupled in population much earlier than anyone had anticipated back in the 1950s and 1960s. Major highway work for the T-REX project ended on August 22, 2006. The COSMIX project was completed in December 2007. Several other smaller improvement projects for I-25 are still ongoing within New Mexico and Colorado.