Sgt. Pete Simpson said Wednesday that Ted Reich was killed Tuesday afternoon. The man's wife discovered him missing earlier Tuesday when she returned from walking their dog.
The spokesman says the man reportedly had wandered before but had not previously left in a vehicle.
Relatives thought he might have been headed to the Portland Yacht Club, a gym or a pub.
The Washington State Patrol says the driver lost control on a northbound I-5 exit ramp, hit a guardrail and rolled multiple times. The accident closed the Maytown Road ramp for three hours.