Video footage from Wednesday’s “Replacing The Tappan Zee Bridge” event is up. Speakers and panelists discussed why New York needs a new bridge — the three-plus-mile span crosses the Hudson between Rockland and Westchester — and how to build it.

One of the most telling comments came from Christopher Waite, former chief engineer of the Thruway Authority, which owns the bridge.

About 1 hour and 31 minutes (and 35 seconds or so) in, Waite notes that “we can’t still be debating this with the bridge closed. It’s essential that something happen.”

What’s Waite talking about? I wrote in my spring City Journal article that as the Tappan Zee continues to deteriorate, one big risk is:

If inspectors decided that a critical component of the bridge was unsafe … the Department of Transportation could shut the span down without warning during one afternoon commute. That’s exactly what the department did in autumn 2009, closing an 80-year-old bridge over Lake Champlain in upstate New York. Despite 20 years’ worth of extensive repairs, including a deck replacement, the cracked [upstate] bridge was unsalvageable; the state blew it up that December. Drivers won’t have a replacement until the end of this year, at the earliest.

Knock the far busier Tappan Zee out, and the economic impact would be much larger. The bridge handles 22 percent of the 233 million vehicles that cross the Hudson River downstate each year. The nearest bridge to the north is 29 miles distant, and its connecting roads can’t handle heavy traffic. The Tappan Zee’s drivers, then, would further clog the already-jammed George Washington Bridge, 24 miles to the south, as well as the Lincoln Tunnel and the Holland Tunnel.

Keep listening to Waite’s remarks (after E.J.’s question) to learn what he would build, including space for freight rail.