Work began this week on a major road improvement project on State Route 21 in Wayne County.  The project, which encompasses a six-mile stretch of highway between the Summit and Stark County lines, is the first major improvement project since the route was built more than fifty years ago.  Single lane closures are expected to begin this week on the four-lane, divided highway. Crews are laying temporary pavement and paving crossovers to move traffic onto southbound lanes and the southbound shoulder. Northbound lanes will be closed this year for construction.