If the money is already raised, why not build a rapid streetcar line between the Colosseum and the Airport terminal with limited stops. Currently the bus line comes every 10 minutes or so and actually makes money. One of the reasons is because its so packed all the time. There have been a few times when I have had to wait for 2 buses to pass in order to get to the airport. Even if the separated the streetcar from traffic, it would not cost $122 million per mile.
With the route I've drawn out below, it would promote office development and for more than just airport riders to take the line and provide a direct link to the airport. It would however be a little bit longer at 3.9 miles, but would get its own lanes and have a consistent travel time. I'm also pushing it through the stadiums because at some point, this land will be much too valuable to just leave as a parking lot and should develop more like urban ballparks and stadiums around the country with proximity to transit. This line could also use value capture strategies to fund improvements or the line itself.

At 3.9 miles, you could certainly build the rapid streetcar for the $250 million already raised. I bet they could have some money left over for other projects.
