If it takes me 40+ minutes longer to ride a subway than drive in (currently true) then it's both me and my employer's interest to reduce cost barriers and pay for the downtown parking.
Tragedy of the commons with a touch of government inertia
Further, I would argue that the time for your commute is to a large part determined by the available infrastructure (roads vs subway lines vs busses, for example), which is something the public has chosen to allocate funds for. There are certainly more and less efficient ways to move people around, and I'm not saying that cars are better or worse, just that the efficiency is partly a choice the public has made.
Or it's in both your interests to decrease the time it takes to use public transport.
Thus if it's in their interest to lobby for a tax code with distortative effects, they will.