The Arizona Department of Public Safety is investigating a serious injury collision in the northbound lanes of State Route 101 at the Red Mountain State Route 202 junction.
At least four vehicles were involved in the accident, said DPS spokesman Raul Garcia.
Northbound SR 101 traffic is being kept on the mainline of SR 101. Traffic is not being allowed onto the Red Mountain SR 202 ramps, Garcia said.
It's not known how long the ramps will be closed.
The Arizona Department of Transportation and the Salt River Fire Department are assisting.
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