So not much.

Ridership has been going down for years in regards to per capita boardings and RTD has raised fares multiple times since fastracks started.  

Transit is cheaper than owning a car and its associated costs but what percentage of transit riders don't own a car?  When I did own a car it didn't make direct financial sense for me to use RTD instead of driving and that's when gas was much more expensive and fares were lower.  

After doing a bit of research I did find a few examples of raising fares = increased revenues but usually it was the opposite.