The Real Chris Christie Transportation Scandal

His cancellation of the commuter train tunnel under the Hudson River:

It's proper now to recall an action Christie took in 2010 that he owned up to quite proudly. This was his unilateral torpedoing of a $9-billion federal-state project to build a commuter train tunnel under the Hudson. The project would have doubled capacity on the route--a crucial improvement given forecasts of sharply rising ridership and the decrepitude of the existing tunnel. It was the largest public transit project at the time, and had already begun. Christie's refusal to approve his state's share killed it.
The cancellation made Christie a darling of the conservative budget-cutting movement, instantly raising his profile as a GOP up-and-comer. Two years later, he was still crowing about his courageous act before conservative audiences.
His depiction of the project was typically blustering and deceitful: "They want to build a tunnel to the basement of Macy’s, and stick the New Jersey taxpayers with a bill," he said. You'd think that was pretty funny, unless you were a New Jersey commuter who knew that the "basement of Macy's" in midtown Manhattan is actually Pennsylvania Station, where the commuter trains go. 
By then, Christie's rationale for killing the tunnel had been exposed as a passel of lies. He had claimed that it would cost more than $14 billion, and that New Jersey would be on a "never-ending hook" for 70% of the cost. In fact, as the Government Accountability Office reported, $14 billion was the maximum estimate, and $10 billion the most likely final bill. And New Jersey's share was 14.4%, not 70%.
But the cancellation allowed Christie to divert the state's share of the tunnel budget to a state highway fund, which in turn allowed him to avoid raising the state gasoline tax--already among the lowest in the nation--by a few cents.

That was such a stupid decision, and all to appeal to the anti-transit Tea Party morons that make up the base of the Republican Party.  Christie came around somewhat and realized that he didn't need to continuously pander to the jackasses of the Tea Party because most of America hates their ideology, but it hasn't prevented Christie from continuing to be an asshole.  I don't believe a word of his claims he didn't know his closest staffers were shutting down traffic lanes just to screw some political adversaries, but of all his moves, cancelling that tunnel was the dumbest.