YELLOWSTONE NATIONAL PARK, Wyo. (AP) — The National Park Service is moving ahead with plans to replace a deteriorating bridge in Yellowstone National Park.

Park officials say the bridge built in 1960 is deteriorating to the point where it could eventually become unstable.

Yellowstone officials said Wednesday construction on a new bridge over the Lewis River could begin as soon as 2020 and continue more than two years.

The park's South Entrance Road would remain open during the work with only brief traffic delays. The new bridge would be built next to the old one.

Nearby parking areas and a trail overlooking Lewis River Falls would be closed during the project.