MASON CITY - There are hundreds of rural bridges in North Iowa whose integrity depends on how much weight is put on them.

On Friday a Mitchell County bridge on Dancer Avenue near Mona collapsed, apparently after a heavy truck rolled over its span.

Shortly after, Otranto Township resident Margaret Meyer, 80, "drove up over the hill (before the bridge) and started coming down - I didn't realize right away that the bridge wasn't there," she said. "I couldn't stop in time."

Meyer's car, which came to rest facing down on a sharp angle toward Otter Creek, was stopped by steel railing that had twisted after the bridge collapsed.

Meyer was trapped on the bridge for about 20 minutes.

"If it hadn't been for the rail, I would have gone in," she said. She and her husband, Loren, live about a half mile from the bridge.

Meyer said she honked her horn off and on for about 20 minutes. Her husband heard the horn and drove to the bridge. He carefully walked down the sharp incline and brought his wife out of the car, bringing her back up the incline.