RAPID CITY, S.D. (AP) – A truck driver accused of causing a fatal interstate crash in Rapid City has been charged with vehicular homicide.

Prosecutors allege Brian Rasmussen admitted he took the insomnia sedative Ambien two days before crossing the median on Interstate 90 Friday and crashing into a vehicle going the opposite direction. Its driver, 64-year-old Karen Bryan, was killed.

A judge set Rasmussen’s bond at $10,000 cash during his initial appearance Monday. His attorney, Chris Christianson, says there’s no solid evidence that proves Rasmussen was under the influence of any substance.

A court affidavit says a drug recognition expert evaluated Rasmussen after the crash and found he was impaired by a central nervous-system depressant, which can slow brain activity and cause drowsiness. The 53-year-old Rasmussen works for Navajo Express, based in Denver, Colorado.

AP-WF-01-29-19 1615GMT