I wonder if a clearly labeled "all trucks go into this lane" well before the tunnel would work. You could have your barrier there, and not impede the rest of the traffic. You could even divert trucks into the car lanes while you clean up.
One one hand, they're already ignoring signs. On the other hand, a sign that says "ALL TRUCKS go this way" might get a better, or at least different, response from "YOU are too tall".
One one hand, they're already ignoring signs. On the other hand, a sign that says "ALL TRUCKS go this way" might get a better, or at least different, response from "YOU are too tall".