BATH — A sport utility vehicle driven by a Windham woman crashed through a guardrail Monday afternoon on the Route 1 viaduct in Bath, plunged about 30 feet from the two-lane bridge and landed upside down in the bed of a pickup truck, police said.

Melissa Medina, 37, and her 12-year-old son, a passenger in the SUV, were taken to Maine Medical Center in Portland, where she was listed in fair condition Monday night. Her son’s condition was not available.

Bath Police Chief Michael Field said the 2003 Mercury Mountaineer went over a concrete barricade in the southbound lane and knocked off about 50 feet of an aluminum guardrail along the top of the barrier. The SUV landed on its roof in the bed of a Ford F-150 pickup truck driven by Roy Ordway, 60, of Bath, near the intersection of Vine and Washington streets.

Ordway was not injured, but the impact crushed the rear end of his pickup truck. Police said Ordway had stopped in traffic for another vehicle when the SUV landed in his truck.

Attempts to reach Ordway for comment Monday evening were not successful.

Field identified Medina as the driver of the Mercury Mountaineer but did not name her son.

The police chief said Medina and her son were extricated from the wreckage and taken to Maine Med with injuries that were not considered life-threatening.

After the accident, the Maine Department of Transportation closed the viaduct to all traffic for about two hours. The department said its road crew had salted the road just a few minutes before the crash because snow was falling.

“We don’t know yet if speed was a factor. We don’t know if roadway surface was a factor,” Field said. He said alcohol does not appear to have been a factor.

According to state records, Medina’s only driving violation occurred in September, when she was convicted of driving with an expired license.

Field said the bridge closure caused a significant traffic backup. Police detoured traffic around the viaduct, which carries traffic over downtown Bath and past the Bath Iron Works shipyard. The crash was reported at 2:36 p.m., near the start of the shipyard’s second shift. Field said traffic was flowing smoothly by 5 p.m.

Fire and EMS services from Bath, West Bath and Woolwich responded to the accident, along with police from Bath and the Sagadahoc County Sheriff’s Department.

Ted Talbot, spokesman for the Maine Department of Transportation, said it appears the impact of the collision “sheared off” the aluminum guardrail on the top of the concrete barrier.

He said the guardrails have been on the bridge for at least several years. MDOT crews inspected the remaining guardrails on the viaduct and found them to be “sound and solid.” The section of guardrail that was destroyed will be replaced Tuesday, starting at 8 p.m. The work could take most of the night.

On Tuesday morning, the MDOT’s chief engineer, Joyce Taylor, and a team of state engineers will review the viaduct’s latest inspection report and use it to determine whether the guardrail performed to expectations.

Under federal law, bridges have to be inspected every two years. Talbot said he did not know when the viaduct was last inspected.

Talbot said the Bath viaduct, which opened in 1958, is due to be replaced this year. Preliminary work on the $15 million project is scheduled to begin next month, with full reconstruction to start in October.

The quarter-mile bridge will be rebuilt in place and look much the same as it does now. More than 18,000 vehicles a day travel over it.

Anyone who may have seen the crash is urged to call Bath police Detective Sgt. Andrew Booth at 443-8367.

Coastal Journal Staff Writer Chris Chase contributed to this report.