The commission was notified of the federal agency's finding Monday.
A bridge to replace the 50-year-old span is needed to ease rush-hour congestion and improve traffic safety, the commission says.
Opponents of the proposed bridge, including the Sierra Club of New Jersey and several New Jersey state legislators, contend it is unnecessary, a waste of money, and harmful to the environment.
The new federal finding accepts the conclusion by the toll commission that "there is no practicable alternative to construction" of the bridge.
The bridge is being designed to use all-electronic tolling, assuming more than 80 percent of drivers will pay their tolls with E-ZPass. Cars without E-ZPass are to be photographed and their owners billed by mail. An administrative fee will be charged to all drivers without E-ZPass.
The bridge commission has not decided how much the one-way (Pennsylvania-bound) toll or the administrative fee will be.
An analysis last year used both a $1 toll and a $3 toll in studying the issue, and that study assumed an administrative fee of $3.50 per trip for motorists who had not registered their license-plate data with the bridge commission and $1.75 per trip for motorists who registered.
Contact Paul Nussbaum at 215-854-4587 or pnussbaum@phillynews.com .
