As the summer months approach, most people turn to thoughts of sunshine, outdoor barbecues and destination trips. Yet travelers often are greeted by detours, lane closures and delays for road repairs that generally are reserved for warmer weather. Researchers at the University of Missouri have studied systems to alleviate inevitable backups and delays. Researchers found that using variable speed limits in construction zones may ease congestion, reduce crashes and make work zones safer for both workers and travelers nationally.