Similar here, but the contract periods tend to be much longer. Like 50 to 100 years before they'll go toll-free, which is just absurd really. And they're not fully private ventures, taxpayer money is spent on these bits of infrastructure.
And the worst part is they don't really do anything to improve traffic long-term. During peak hour, it's not unusual to jump in the tunnel only to be stuck in the same gridlock traffic as you'd be in anyway, only you just paid 6 bucks for the privilege.