Is it that there is NO parking in downtown Seattle? or that there is no free/cheap parking in downtown Seattle? I haven't been there in years (don't care for the place) I live on the dry side.
I suppose there might be very specific circumstances where your employer could be legally responsible for your safety when away from the work location, but that would be a very unusual situation.
Generally speaking, the law doesn't care how awkward, impractical, or expensive your alternatives are, as long as you have alternatives, they are unlikely to find your employer responsible for your personal safety to and from work unless the company picks you up at your doorstep and drops you off after work. It's not their fault that you have to take the bus....etc.
All else being equal (and it almost never is) bigger bullets tend to work better.