The Bronx River Parkway pioneered grade-separated, landscaped limited-access highways

Evidence

As he thought about the road, he thought about the Bronx River Parkway. Although it hadn’t yet been opened, the newspapers were full of stories about it. With the exception of a three-mile stretch of the Fenway in Boston and, of course, the transverse roads in Central Park, the parkway would be the first highway in the country to eliminate traffic lights and intersecting traffic by lifting all crossroads above it. The bridges that carried the crossroads would be faced with stone to blend in with the scenery, and the bordering right-of-way would be completely landscaped. Newspapers were predicting that it would be the most beautiful road in America. — Robert A. Caro, The Power Broker, 719