There is great potential for something like Lyft to fix the rail "first mile" and "last mile" problem. If they can integrate systems with government so that the Lyft cost is part of the rail fare, then it's possible it could be covered by the commuter tax benefit. That would be a big win for everyone, lower cost for commuters, steady income for Lyft, increased ridership for rail.

EDIT: The more I think about it, this is such a good idea I hope Lyft is seriously working on this. With something like Lyft Line, the optimization potential is immense. Assuming each Lyft Line car can have 3 passengers and most workplaces would be within 2-3 miles of a rail station, rides could be very cheap and fast. For example, most coworkers going home would probably share the same Lyft back to the station. The short distance (assuming a 2-3 mile radius) combined with Lyft Line would allow very high throughput during rush hours. If the Lyft cost can benefit from the commuter tax deduction, that's just icing on the cake since the car sharing alone should drop costs by a lot. And there's also networking effect. Coworkers will want to encourage coworkers to do this so they can lower costs for everyone.