*** Finally it works on iOS 5 ***

This is an iPhone/iPod Touch native application to help you find best metro routes without internet connection (it works while inside the metro).

Cities currently available are: New York, Boston, L.A., Paris, London, Madrid, Barcelona, Vienna, Milan, Rome. You may install as many as you like (cities information is free). For every city the program provides: best-routes calculator, a map, and the link to the official web site.

This application obtains three different types of optimal routes:
1) Fastest: shortest time
2) Easiest: minimum number of line changes
3) Accessible: handicap accessible (making line changes only at stations with handicap access)

Routes are obtained instantly because they are pre-calculated. In other approaches the applications need to compute every case during seconds or even minutes for large metro networks such as New York, Paris or Madrid (after including "metro ligero").
All route times are estimated from typical line speeds and connection times, so they may not be accurate.
Handicap routes are computed according to the information published by Metro companies.

iMetro Multi-city is the native version of iMetro web application, which is available for free and open source (javascript).see http://www.iit.upcomillas.es/imetro. Although the algorithm of iMetro WebApp is completely implemented in JavaScript and therefore it can be run without Internet connection, it is not valid for large metro networks because computational load exceeds iPhone capabilities (solving the optimization problem in a mobile device requires too much time to be useful).
In iMetro Multi-city all possible routes are pre-calculated and stored in a database which is downloaded to your iPhone when you install a city (Internet connection is only required while adding cities). The same databases are available in a web application called iMetro PHP that requires active Internet connection, it's free, and can be used to evaluate iMetro Multi-city.