In the next year or so maybe. The biggest obstacles to adding public transit are:

- Collecting all the necessary scheduling data (e.g. GTFS feeds) for every transit system in the county. Not insurmountable since there are services that do this currently.

- Finding a routing engine that can compute nation-scale travel time matrices quickly. Currently, the two fastest open-source engines I've tried (OSRM and Valhalla) don't support public transit for matrix calculations and the engines that do support public transit (R5, OpenTripPlanner, etc.) are too slow.

Can you just compute the travel times from each bus/train/tram stop and publish the individual or merged travel times? I guess the merging would be the hard part

I would imagine actual nation scale public transit would be relatively difficult since even in the Northeast transit networks are often not contiguous

I feel like this would have to come from Apple/Google, due to them having numerous real time datapoints on the time it takes from the origin public transit stop to the destination transit stop.

And then they could determine the variance at certain times of days for certain public transit routes, and show your likelihood of reaching the destination by a certain time.