Time saving Iphone app?

For everyone that has ridden a NYC subway, you know that they can be crowded, complicated, and confusing. I was shown this curious little app for the Iphone the other day, Exit Strategy NYC, an application with a feature known as "Platform Strategy". One thing that this brother and sister creative duo thought of was how to make your subway experience a more easy and efficient one. They were able to determine after many subway hours what subway car you should be in depending on you desired destination, for every subway stop in the city. They spent a lot of time riding the subway, finding out which car was closest to the exit, so you could save 10-30 seconds here and there. For someone who rides the subway 30 times a week, that could add up to almost 12 hours a year. The app also has subway and bus maps for the whole city, and only costs $4.99. Next step tube travel...