The California Highway Patrol is looking for the big rig, which did not stop.
The incident occurred on Saturday at about 10:05 a.m. on northbound SR-99 south of Fruitridge Road in the Sacramento area.
The victim is in stable condition.
The CHP says after the metal bar fell of the big rig, it bounced up and entered the right front of the car and traveled through the engine compartment to enter the passenger area.
Officers from the South Sacramento Area and personnel from the Sacramento Fire Department then rushed to the site and rendered aid.
If you witnessed the incident or know where the big rig is, please contact Officer Jim Young at (916) 681-2300 or by email at email@example.com.