WEST DES MOINES (AP) — Plans by Microsoft Corp. to build a nearly $600 million data center in West Des Moines are on track, despite the ailing economy.

City Manager Jeff Pomeranz says the software giant plans to start construction next spring or summer.

The Iowa Transportation Commission on Tuesday approved a state grant of $3.4 million to the city to cover half the cost of road improvements to provide access to the site. The city will provide a local match.

Microsoft announced plans for the data center in August. It will help handle millions of Microsoft online functions each month, such as Hotmail and Messenger instant messaging services.

Microsoft was founded in 1975 and is based in Redmond, Wash.