On the Thursday, Oct. 3, episode of Sundial: Senator Manny Díaz Jr. On Transportation And Education Republican State Senator Manny Díaz Jr., representing District 36, which includes Hialeah, is pushing for legislation that would dissolve the Miami-Dade Expressway Authority (MDX) and create a new entity called Greater Miami Expressway Agency. Under GMX, toll rates would remain in place, but the governance structure of the toll board would change and be run by county and Tallahassee appointees.