Investigators said the boy was caught after he posted "somehow the police haven't found me yet" on Facebook.
Then, they tracked him down at Sam Barlow High School.
Police believe the boy stole a van from a tree farm and then drove it onto the highway east of Gresham.
The van sideswiped an SUV late Tuesday afternoon and then rolled.
The boy, whose name will not be released since he is a juvenile, was arrested late Wednesday.
He was booked into the Donald E. Long Juvenile Detention Facility for felony hit-and-run and unauthorized use of a motor vehicle.
A witness reported seeing the driver of the van running from the scene.
A K9 team followed a scent to west Stone Road and lost it.
The silver 1999 Ford Van was westbound on U.S. 26 just before 5 p.m. when it drifted onto the center grass median.
The driver over-corrected, came back onto the westbound lanes and sideswiped the BMW.
The van continued west for a bit, rolling and coming to rest upright across both eastbound lanes, according to Lt. Gregg Hastings with Oregon State Police.
Dean Jackson Pace, 52, who was driving the BMW SUV, was taken to Oregon Health and Science University in critical condition and later upgraded to serious condition, Hastings said.
He suffered several broken ribs a ruptured spleen and a punctured lung.
Pace was wearing his seat belt and the SUV's airbags deployed.
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