UPDATE | All lanes have been reopened, ODOT reports.
MEDFORD, Ore. -- Oregon Dept. of Transportation has issued a traffic alert for southern Oregon drivers.
The slow lane of Interstate-5 southbound at milepost 28 in Medford is blocked by a crash, with traffic backed up onto the Medford Viaduct, ODOT reports.
"Expect congestion and delays southbound leading to Exit 27, the south Medford interchange," ODOT said.