If you're the contract negotiator, finding a single company that won't complain about the kickbacks you ask for is easier than finding a bunch of them, right? And what's the point of working for the Port Authority if you're not going to be corrupt? This is the agency that snarled traffic in the town of a mayor that wouldn't endorse a candidate of the opposite political party, mostly just for the lulz. Predictably, the structure of the Port Authority ensures that nobody can ever be held accountable, and indeed, nobody was.
(If you didn't follow Bridgegate when it was happening, strap in for the most petty government overreach you've ever read about. I've read this article a number of times and honestly, you start reading and you can't look away. It's so good! https://en.wikipedia.org/wiki/Fort_Lee_lane_closure_scandal)
Not quite. One of Christie's appointed directors at the port authority closed the bridge. Later the port authority decided to reverse it's own decision.
The intro blurb skips the appointed director and attributes the closing of the bridge directly to Christie, but Christie acted through a crony at the Port Authority, as can be read further in the Wikipedia article.
(If you didn't follow Bridgegate when it was happening, strap in for the most petty government overreach you've ever read about. I've read this article a number of times and honestly, you start reading and you can't look away. It's so good! https://en.wikipedia.org/wiki/Fort_Lee_lane_closure_scandal)