This is the worst answer of all. (Sorry.) As Christians, we are called to reject materialism and consumerism to the greatest possible extent. We also have to embrace asceticism as much as we are able. This means prudent use of the world's goods and selfless stewardship of the Earth and its environment. Short automobile trips which could easily be undertaken on foot simply do not fit into this philosophy. We must strive to avoid any unnecessary use of automobiles, which pollute the air, promote selfishness and isolation, and push people too much into the "rat race."
Also, far too many people need much more exercise than they now get. Walking and bicycling are both excellent ways to combine transportation and exercise at the same time. By all means, consider leaving the car home the next time you go to Mass (regardless of how far you have to walk). The worst way to prepare for Mass is to fight other aggressive drivers who are prepared to kill you in their mad dash to wherever they are going-- especially if you become one of them! Walking may be an acquired taste, but it's well worth the trouble.