By Jared Ebersole in Video — 27 Jun 2026

The Hidden Roadway Under the George Washington Bridge

The George Washington Bridge became the world's busiest motor-vehicle bridge by adding a second roadway beneath the one everyone sees.

From a distance, the George Washington Bridge looks almost simple.

Two steel towers. Four main cables. A long roadway crossing the Hudson between Washington Heights and Fort Lee. The secret is that the most important upgrade is not the part most people look at.

It is underneath.

Where it crosses

George Washington Bridge, between Fort Lee, NJ and Washington Heights, Manhattan, NY

When the bridge opened in 1931, it was already radical. The Hudson was too wide for an ordinary crossing, so chief engineer Othmar Ammann designed a suspension bridge with a 3,500-foot main span, at the time the longest in the world. The bridge had to be light, efficient, and flexible enough to make the leap between the Palisades and Manhattan.

That lightness made some people uneasy.

The towers were enormous, but the roadway looked thin. The original plan included stone cladding for the steel towers, but the covering was never added. Depression-era cost pressure helped leave the towers exposed, and the bare steel skeleton became one of the bridge's defining features. What looked unfinished to some became an icon of structural honesty to others.

The bridge worked better than anyone's nerves.

It opened with six traffic lanes. Demand grew quickly. In 1946, the upper roadway was widened from six lanes to eight by converting unused space on the deck. That helped, but it did not solve the real problem: the bridge had become one of the region's essential road corridors, and the metropolitan area kept feeding it more traffic.

The surprising part is that Ammann had planned for this.

The George Washington Bridge was conceived with room for another level below the original roadway. Early plans even imagined rail tracks on a lower deck. The Depression delayed that idea, and rail never arrived. But the space remained, waiting for a different use: six more lanes of cars and trucks.

Building that second deck was not like adding a basement.

From 1959 to 1962, workers installed a new lower roadway while traffic continued above them. The existing suspension bridge was alive with movement. Steel expands and contracts with temperature. The deck shifts under load. Wind moves the structure. A rigid addition bolted into place as if the bridge were frozen could have fought the original bridge instead of moving with it.

So the lower level had to become part of the bridge's motion.

Engineers used expansion joints, pins, and flexible connections that allowed the new steel framing to adjust as the older structure moved. The lower roadway was not simply hanging below the bridge. It was negotiating with a bridge already carrying one of the busiest traffic loads in the country.

The lower deck opened on August 29, 1962.

It added six lanes, bringing the total to 14 and increasing the bridge's capacity by about 75 percent. The Port Authority notes that the George Washington Bridge is now the world's only 14-lane suspension bridge. It is also widely described as the world's busiest motor-vehicle bridge, carrying more than 100 million vehicles in many recent years.

That success created its own contradiction.

Adding lanes made the bridge more powerful, but it also made the bridge more indispensable. The GWB became less a single crossing than a machine for feeding Interstate 95, the Cross Bronx Expressway, the Trans-Manhattan Expressway, Bergen County highways, freight routes, commuter traffic, and the entire logic of driving through the New York region.

The tolls followed the traffic.

Cars once crossed for 50 cents. Adjusted for inflation, that is still far below what many drivers pay today. The GWB became a major revenue engine for the Port Authority because it sits at one of the most valuable choke points in the region: a place where millions of trips have no equally convenient substitute.

That is why the hidden lower deck matters.

It is not just an engineering curiosity. It is the moment the bridge became the traffic machine we know now. The upper deck made the leap across the Hudson. The lower deck turned that leap into a 14-lane corridor that could carry an astonishing volume of vehicles while making the region even more dependent on it.

The George Washington Bridge still looks unfinished to some people because its towers were never dressed in stone.

But the more interesting incompletion was intentional.

A second bridge was waiting inside the first one.