Advance Auto Parts is a leading auto-parts retailer in North America with more than 4,000 store and branch locations. About 50% of the firm's sales are geared toward the professional channel, with the remaining sales in the do-it-yourself market. Through its vast store footprint and distribution network, Advance manages thousands of stock-keeping units for various vehicle makes and models. The retailer primarily competes on the basis of inventory availability and service speed, making the operating efficiency of its hub-and-spoke distribution model critical to meeting customer needs.