Construction expands outward as low availability pervades central areas. The market has grown by an average of 5,300 people per month since 2010, increasing demand for distribution space to meet rising consumer needs, contributing to a 650-basis-point drop in vacancy over that time span. Less availability has spurred development, predominantly outside the urban core. The I-81 Corridor will receive much of 2019’s construction pipeline, with the 1.2 million-square-foot I-81 Industrial Center underway in Hagerstown, Maryland. The toll-free highway offers a less-trafficked alternative to I-95 for transit into Philadelphia and New York, while a local average asking rent under $5 per square foot appeals to tenants. Elsewhere in the market, there are fewer deliveries, facilitating lower vacancy in submarkets including the Dulles Corridor and Manassas/I-66. Urban density caps new supply inside the District to 16,000 square feet this year.