A two-vehicle crash on the A470, between Church Street in Rhayader and the Llangurig roundabout, happened shortly after 11:45 GMT on Friday.
It affected motorists travelling between Builth Wells and Llanidloes before the road reopened by 17:30.
The A483, north of Welshpool, was later shut after a crash involving five vehicles just before 15:00 and the road remained closed into the evening.
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Daniel Begg, 21, of Dundee, admitted culpable and reckless behaviour.
The fan who was struck avoided serious injury in the incident at Pittodrie Stadium on Sunday 25 September.
Begg was fined Â£260 at Aberdeen Sheriff Court. The court refused a Crown motion for a football banning order stopping Begg from attending future games.
Rangers fan Begg was in the away end at Pittodrie.
Police had earlier issued a CCTV appeal to trace him.
Two Powys roads were forced to close after separate serious collisions.
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A football fan who threw stadium seats at another supporter during an Aberdeen v Rangers game has avoided a ban from matches.