Cintra is putting up front $7.2 billion in funding for the new corridor.
By the way, you are flat wrong about the diversion of the gas tax revenues. The legislature can't "do whatever they want with that money," nor can they end the diversion tomorrow as you claim. The Texas Constitution (article 8, section 7-a) requires that 1/4 of the gas tax SHALL be allocated to the Available School Fund. Unless you're calling for the complete suspension of the constitution, which I admit I've missed in your previous posts, the legislature would first have to pass a constitutional amendment, which requires 2/3 of both houses, then it goes on the ballot, and then if a majority of voters agree with you, which I'm guessing they wouldn't, then the legislature could change the funding the next time it writes a budget, in 2 1/2 years. We could get toll roads built quicker than that.
"By the way, you are flat wrong about the diversion of the gas tax revenues."
My apologies then - I'm not an expert on the inner workings of Austin. I only know what I read - and I hadn't seen it either way - either in the Constitution or as legislation, so I certainly won't dispute what you say. I just figured that the this was simply legislation, as it is done at the federal level.
So, yes, it would take the same process that gave us the Constitutional Amendment(s). And, yes, it's certainly tougher to amend the state constitution, then simply passing legislation.
On the other hand, the constitution was amended to allow "creative" financing of highways, and virtually no one had any clue of what was in store for us.
So, for the time being, the schools can keep their 25% share, for all I care, and we can raise the gas tax a bit more to cover (of course, since money is fungible, there are other ways to cover the education diversion, if they want to do so).