Sergeant Blair Wilkinson, of Oamaru, said early indications were that fatigue was probably a factor in the single-car crash that happened about 1.15pm, near the intersection of State Highway 1 and Richmond Rd, about 11km north of Oamaru.
The crash ignited a grass fire which at its peak stretched for about 40m alongside the highway, near the main trunk railway line.
The male driver and sole occupant of the sedan escaped without assistance, and was taken by ambulance to Oamaru Hospital with unknown injuries.
Firefighters brought the fire under control shortly before 2pm.
At the same time the highway was reopened, after having been closed in both directions for about 45 minutes.
Network Waitaki engineering manager Brad Fleming said about 290 customers’ electricity was affected.
"Fortunately, we were able to do some quick restoration, so a lot of people were back on in good time."
The condition of the man involved in the crash is not known.
