The Port Authority held an emergency drill in the Holland Tunnel Saturday night to allow firefighters to practice responding to a fire there.
Three cars were set on fire inside the tunnel as a simulation.
The drill was also a test of the tunnel's smoke ventilation system.
Port Authority officials said that getting smoke out of the tunnel saves lives.
"The ventilation is the lifeblood of the tunnel. It's so critical to vent this tunnel in an emergency," said Anthony Carvagno, the general manager of the Holland Tunnel. "And the smoke is always pulled away from the customers. So if the fire is in front of you, the smoke is going to be pulled away from you. So if the customer's behind the fire, he'll always have good fresh air. The smoke is pulled away."
The New York City Fire Department, the Jersey City Fire Department and other agencies participate in a drill at the Holland Tunnel every year.