One person is in critical condition and at least two other people were injured after two severe crashes — one a head-on collision, the other involving a motorcycle — occurred Tuesday on U.S. 1 in the Keys.

At about 6:30 p.m., a 2004 Nissan X-terra was driving north on U.S. 1 and crossed into the south lane at mile marker 29.5 near Pine Channel Bridge. A 2005 Chevrolet truck, driving south, swerved to the left but still collided with the Nissan sedan.

The Nissan driver, who was not wearing a seat belt, was airlifted to Ryder Trauma Center at Jackson Memorial Hospital in critical condition, Florida Highway Patrol officers said. The driver and passenger from the Chevrolet were taken to Fisherman’s Hospital in the Keys.

The road reopened just before 9 p.m., officers said.

Another crash involving a motorcycle at mile marker 97 blocked one southbound lane on the Overseas Highway.

Monroe County Sheriff deputies and Florida Highway Patrol officers have not released details about the second crash.

Two people died Monday night and two others were airlifted to Ryder Trauma Center after a head-on crash at mile marker 38.8 Monday. Sixteen people have died on the highway in Monroe County since the beginning of the year.