WASHINGTON — A 108-year-old statute — partly designed to keep steamboats moving freely — could give federal prosecutors the grounds to pursue cases in Bridgegate.

The Bridge Act of 1906 provides broad guarantees for interstate commerce on bridges that span US waterways.

“It does come with teeth. There could be some serious consequences,” a DC source said.

New Jersey’s US attorney has announced that his office is investigating the traffic mayhem last September.