The city of Des Moines will launch its experiment today with unrestricted parking on a few downtown streets. In an effort to promote business activity and enhance walkability, the city will bag meters on Locust, Mulberry and Seventh streets. A press conference is scheduled for 1 p.m. with Mayor Frank Cownie, City Manager Scott Sanders and real estate attorney Larry James, who is chairman of Urban Land Institute Iowa. The streets affected are Seventh from Martin Luther King Jr. Parkway to Interstate 235; Locust from 17th Street to Second Avenue; and Mulberry from 15th Street to Fifth Avenue.