I guess, and I realize they have you over a barrel. You really don't much of a choice if you are going to live there.
Given that I probably burn a gallon each way, (3.39/gal) given 40 trips per month let's say considering both ways, that is $135.60 in gas alone, not considering wear and tear. I am guessing HIAR would drive s shorter distance, but would pay a princely sum in parking. In any case, if you can make it work with your schedule, seems a good savings to me.
So my drive is not much further than yours. (12 miles each way). Considering costs of insurance, fuel, wear and tear, upkeep, costs of financing if any, license tabs, etc., you are money ahead not to own one, if you don't need one otherwise. Given my outdoors activities, I would find it hard not to have a vehicle available for free time adventures. But even leaving out the already sunk costs of ownership (tabs, insurance, financing), if you consider only operational costs, you are money ahead if you can use that public transport instead of commuting by car. But you already know that.It's about 10 miles between home and work. The drive time would be about the same as the train time. We figured it out, and given local costs, it wouldn't make sense to have a car unless we were spending upwards of $500 per month on a ZipCar. They're parked in the lot down the block from us and are easily reserved. It's just not worth it; not in parking tickets, monthly lot fees, or insurance. And that's before I even get into said car to drive it.