Area overview - slow traffic through Upland, Norco, Corona 7:31 a.m.
Heavy traffic is on the westbound 10 Freeway at San Antonio Avenue and the eastbound 10 at Benson, according to Caltrans. There's also some congestion on the southbound 15 Freeway at Limonite in Mira Loma, the northbound 15 at Fourth Street in Norco and the westbound Highway 91 at Main Street in Riverside.