On November 13, 1927, the Holland Tunnel opened to vehicular traffic and connected Manhattan to New Jersey for non-train travel for the first time. While the entire undertaking was a monumental achievement, it was the ventilation system that required the most revolutionary development and implementation, and without which the tunnel could never have happened.
Creating a Hudson crossing was no small feat. The initial thought was to build a bridge, but at the desired endpoint in lower Manhattan there was far from enough space to construct onramps leading up to a span that would have to be 200 feet above the water’s surface to enable continued shipping activity in the harbor. Tunneling under the Hudson had become a reality with the recent construction of train tunnels serving lower and midtown Manhattan from New Jersey. It was resolved that this new vehicular passageway would also be a tunnel, the very first of its kind.
No one had built a tunnel for cars before, likely as they hadn’t been around all that long when the design process began on the Holland Tunnel in 1913. The biggest hurdle was that of emissions: cars, with their noisy and polluting combustion engines spewed noxious fumes into the air. With the planned length for the tunnel over a mile long, it was certain that these airborne chemicals would be inadequately expelled through normal airflow between the open ends of the tunnel and could suffocate and harm those passing through. The chief engineer of the project, Clifford Holland, turned to Ole Singstad, a young engineer from the railway business, to take a crack at solving the ventilation issue.
Singstad designed an ingenious system. By constructing four ventilation towers, two on either end of the tunnel, huge sets of fans could blow in and then suck out air from the tunnel below. Fresh air would be forced down into the main tunnel tube, entering at about curb-height. Simultaneously, polluted air from the tunnel tube was sucked back into the ventilation tower from the tube ceiling. The system worked perfectly, and at peak operations it can freshen the entire tunnel with clean air in around 90 seconds, leaving the tunnel air at times even cleaner than the air outside.
His design was so well regarded that Singstad was, over the years, invited to design other tunnels for the city. He is responsible, in part or in full, for the designs of the Holland, Lincoln, Brooklyn-Battery, and Queens-Midtown tunnels. His ventilation system became the standard for auto tunnels around the world, and the original system is still humming along nearly 90 years after he installed it in the Holland Tunnel.