On this day in 1927, Time magazine puts the week-old Holland Tunnel on its cover. The tunnel, which runs under the Hudson River between New York City and Jersey City, New Jersey, had opened to traffic the week before, at the stroke of midnight on November 13. (Earlier that day, President Calvin Coolidge had ceremonially opened the tunnel from his yacht on the Potomac by turning the same key that had "opened" the Panama Canal in 1915—Time called it "the golden lever of the Presidential telegraphic instrument"—which rang a giant brass bell at the tunnel's entrances.) On that first day, 51,694 vehicles traveled through the tunnel.
Time presented all of the tunnel's vital statistics: its total length (9,250 feet, the "longest of its kind in the world"), length under the river (5,480 feet), hourly and yearly vehicle capacity (3,800 and 15,000,000, respectively), excavation (500,000 cubic yards of soil and rock) and cost ($48.4 million). It also explained the most significant thing about the tunnel: its sophisticated ventilation system.
Until its engineers could figure out a way to keep carbon monoxide out of the air, building an underground road for cars and trucks had been a foolishly dangerous idea. A team of scientists from Yale, the University of Illinois and the Bureau of Mines discovered that only four parts of the poisonous gas per 10,000 of air could be lethal, and they recommended that the tunnel's builders design a two-duct ventilating system to ensure that people in the tunnel would always have fresh air to breathe. As Time explained: "To prevent disaster absolutely Chief Engineer Holland installed 84 ventilating fans in four 10 story buildings, two on each side of the Hudson. Part of them blow fresh air into the tunnel floor through vents, others suck vitiated air through ducts in the tunnel ceiling. Thus they change the tunnel air completely 42 times an hour and but 56 of the fans are needed to do so." (The other 28 were reserved for emergency use.) It took—and still takes—about 90 seconds to replace all of the air in the tunnel with fresh air.
On the day the tunnel opened, the toll was 50 cents per car in both directions. In 1970, the Port Authority of New York and New Jersey switched to one-way tolls. By 2009, the one-way toll was $8.