ST. CATHARINES, Ont. — A couple managed to flee their pickup truck just seconds before a massive concrete block was lowered from a bridge and crushed it nearly flat Monday afternoon.

Retiree Ernie Duff and his wife escaped mere heartbeats before the counterweight of the Lock 1 bridge over the Welland Canal came down.

"At the last minute my wife and I bailed out. Ten seconds later, the car was crushed," Duff said.

"I'm just thankful we got out of the truck."

It happened around 3 p.m. at Lakeshore Rd. and the Welland Canals Parkway in this southern Ontario city.

Staff Sgt. Tim Carter said Duff has been charged with running a red light.

"He basically drove up to the bridge and saw the cars on the other side," Carter said, after reviewing video from the scene. He said the traffic arms came down as Duff tried to get away.

"He sat there for quite some time" before he and his wife bailed out, Carter said.

A crowd gathered around the lock as the truck — squashed down to the tops of its front doors — was extracted from under the huge concrete counterweight.

Duff said there wouldn't have been room to even lie down on the seats had they remained inside.

Seaway maintenance manager Joe Vlasic said officials are investigating how the truck got under the weight.

"We need to investigate what happened, exactly. It's ongoing," he said.

Vlasic said Seaway implements preventative systems to keep crossings safe.

Duff said he stopped when he saw the red light on the other side of the bridge and the line of cars waiting there. He said he tried to back up, only to find the traffic arms pinning him in.

A former St. Catharines resident who now lives in Florida, Duff said he's driven over the bridge many times in the past.

"They've got to be able to stop that thing," he said.