A deadly crash on Interstate 84 west of Arlington has claimed one life and left an Oregon Department of Transportation employee critically injured.  The crash happened Tuesday afternoon at about 2:40 near milepost 123.  The Gilliam County Sheriff’s Office says according to the preliminary investigation, an ODOT employee from the Arlington Maintenance Station was helping a motorist change a tire near milepost 122 on westbound I-84.  The ODOT vehicle was parked on the shoulder with its amber warning lights activated and an illuminated message board directing traffic into the far lane.  Investigators say an approaching vehicle struck the rear of the ODOT vehicle, then hit both the ODOT employee and the motorist.  The ODOT employee suffered critical injuries and was flown to a regional trauma center.  Officials say the employee remains in critical but stable condition.  The motorist died at the scene.  The Oregon State Police is investigating the incident.