Drivers who travel on Route 28 through downtown Randolph may want to look for detours this Saturday. Crawford Square, from Warren to South Main streets, will be closed to vehicular traffic from 12:30 to 5 p.m. for Winterfest 2012, a street festival organized by the town and the Randolph Chamber of Commerce. Thousands of residents and visitors are expected at the event, which evolved from the annual Holiday Lighting and Stroll. This year’s event, scheduled from 1 to 4:30 p.m., will feature stage and street performances, and the Randolph High School band will lead a “holiday stroll’’ for the annual lighting of the trees. “We are excited to showcase Randolph businesses in our recently completed Crawford Square, and see Winterfest as an opportunity to attract new customers to commercial opportunities in Randolph,’’ the Chamber said in a statement. For a schedule of events, visit www.RandolphChamberofCommerce.org or become a member of the Facebook page, Randolph Winterfest, for automatic updates.