The completion of I-27, costing a total of $453.4 million, encouraged growth along the highway: towards the north side of Lubbock and the southwest in Amarillo; Canyon has become a suburb of Amarillo. Plainview, the largest city between Lubbock and Amarillo, has the only significant retail cluster outside the two terminal cities, and has attracted several industries. On the other hand, Tulia, once a self-contained community with local businesses, was bypassed by I-27, and residents must now drive elsewhere for most shopping needs.