A crash on I-85 that left a driver critically injured Thursday afternoon appears to have been caused by a medical emergency, authorities said.

Troopers responded to a crash involving an SUV and a tractor-trailer about 4 p.m. in Gwinnett County, the Georgia State Patrol said. The wreck took place on the I-85 South exit ramp to Ga. 317.

The SUV’s driver suffered an apparent medical emergency before the crash, leading to the wreck, the GSP said. The person drove under the big rig’s trailer.

According to the WSB 24-hour Traffic Center, the exit ramp was closed for about 30 minutes before reopening.

The SUV’s driver was critically injured. No other information on the driver’s injuries were provided.

On Wednesday, a similar wreck took place within the same two-mile stretch of I-85.

The driver of an SUV is accusing of losing control, hitting a guardrail on I-85 North near I-985 and being struck by a tractor-trailer, AJC.com previously reported. All but one lane of I-85 North was blocked for about two hours.

MORE: I-85 in Gwinnett reopens after SUV hits guardrail, tractor-trailer, GSP says

Troopers are investigating both crashes.

In other news:

Five people, including 3 children, were killed in the crash.