And although the I-55 submarket saw its vacancy rate rise to 10.86%, or about 100 bps since 2013, Colliers attributes this to what it calls “an explosion of new construction deliveries in 2014.” Developers completed speculative developments totaling 1.8-million-square-feet, surpassing the 1.3 million-square-feet of build-to-suit completions.

What impresses Rosenberg most about this development is the range of building types and the already-proven demand. Pizzuti Co. built 672,100-square-feet at Pinnacle Business Center in Romeoville and IDI Gazeley finished a 602,800-square-foot building at Bolingbrook Corporate Center West. But in addition to these structures, which large users should find appealing, developers also put up smaller specs.

Principle Construction Corp., for example, recently began construction on a new spec warehouse at 900 Windham Parkway in Bolingbrook, and significantly, landlord Clarion Partners quickly signed Berlin Packaging to a lease for 125,478-square-feet of the 237,000-square-foot building.

Deals like that have become common, Rosenberg adds, and it's a sea change from just a few years ago. “Capital did not just get scared during the recession; it got beat up. If you had a vacant building there was nothing you could do about it.”

And even though the I-55 submarket's 3.1-million-square-feet of new construction led all others with 27.2% of the regional total, builders have launched projects all over Chicagoland. Forty-five new projects were started in 2014, with thirteen in the fourth quarter alone.

Rosenberg expects that developers will keep up the pace in 2015, especially for the small- to medium-sized users. For several years, many of these companies “have done everything they could to avoid a move,” either by making do with their existing space or perhaps just expanding into adjacent facilities. But with customer demand increasing for so many businesses “their need for more space is not going away; that part of the recovery is just beginning.”