For me, it really depends on the place I want to go. Most of the time I take the public transportation cause it is much cheaper and I don't have to worry about where to park my car. I prefer the metro or subway, there is no traffic and the trains usually arrived on time.
I think the cost of parking, operating a car along with insurance are the figures that are used when compared to the cost of taking public transportation. If you look at the cost of gas for the car compared to the fare to get on the bus the bus may not be cheaper.