We consider fast-tracking to be tripling the current capacity, therefore you may answer as though the estimated cost would be to install 10 additional high-quality pedestrian crossings per year. At $200K each that would be $2Million.
Other factors for consideration: Note that a single pedestrian fatality "costs" more than $1Million in insurance and lost earnings.
For more information, please see: https://winnipeg.ca/publicworks/trafficControl/pedestrianSignals/pedestrianCrossingControl.stm