CUPERTINO -- A woman struck and killed by a big rig while walking in a crosswalk Tuesday has been identified as Xiulin Du, 79, of Cupertino.

The accident happened around 7 a.m. at the intersection of Foothill Boulevard and Cupertino Road, said sheriff's officials.

Du, who was identified on Thursday by the Santa Clara County Medical Examiner's Office, was walking in a marked crosswalk headed west across Cupertino Road when she was hit by the big truck, which was going south on Foothill in the far right lane.

The driver of the big rig was said to be cooperating with the investigation, and sheriff's officials said Tuesday that drugs or alcohol did not appear to be factors in the crash.

Contact Eric Kurhi at 408-920-5852. Follow him at Twitter.com/erickurhi.