The massive Route Fire burning near Castaic is causing major traffic delays for truck drivers and commuters Thursday.

After a full closure Wednesday night, officials had begun reopening the freeway Thursday morning, but the relief to commuters would prove to be only temporary.

Aerial video from Sky5 around 8:15 a.m. showed the northbound side of the freeway had been reduced to just one lane.

The lane reduction extended from Lake Hughes Road to Templin Highway, according to a tweet from Caltrans.

“Caltrans is assessing the structural integrity of one portion on the northbound side,” California Highway Patrol Capt. Ed Krusey said during a Thursday morning news conference.

Officials would determine if they can open an additional lane once the area was evaluated by an engineer, Krusey said.

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Video showed trucks and cars at a virtual standstill all the way back to Parker Road as of 8:30 a.m.

Vehicles on the southbound side of the 5 Freeway, which had two lanes reopened earlier Thursday morning, appeared to be moving smoothly.

The two lanes were left closed to allow for the transport of fire equipment through the area, Krusey said.

“Once we no longer need to have fire out there, we will open it back up as soon as it’s safe,” Krusey said. “Right now we want to make sure the safety of the fire personnel are paramount.”

Eastbound Templin Highway at the 5 Freeway and northbound Ridge Route Road at Northlake Hills Elementary School were also closed.

Drivers who tried to use San Francisquito Canyon Road as an alternate to the 5 Freeway ran into another headache.

An Amazon truck failed to navigate a turn, prompting officials to shut down that roadway in both directions since around 12:30 a.m.

The Route Fire erupted south of Castaic Lake along the 5 Freeway Wednesday.

As of Thursday morning it had burned 5,208 acres and was 12% contained.