Heavy traffic is expected through this weekend on Interstate 35 as thousands head to Duluth for Grandma’s Marathon. MN-DOT’s Kevin Gutknecht says there’s road construction between Pine City and Hinckley, and I-35 is one lane each direction. He says motorists need to approach that area carefully and should consider alternate routes. Gutknecht says there could be lengthy backups on I-35 in the Pine City/Hinckley area.