Traffic came to a stop on the northbound 125 freeway after a car rolled over.
The accident happened at about 6:15 a.m. on the northbound 125 near Jamacha Rd.
A person appeared to be laying on the side of the road out of traffic's way. The person's condition is not known at this time.
As CHP officers and emergency crews responded, two lanes were blocked.
Lanes were opened by 7:30 a.m. but traffic was still slowed to about 15 mph, according to Sig Alert.