Usually, it takes around 25-30 minutes by bus to commute from my apartment to lab at the UniKlinik Heidelberg. I took a regionalbahn (regional train) from Heidelberg to Frankfurt in Sunday, and the journey took around 1 hour and 35 minutes.
I have visited many cities throughout Germany so far on my Fulbright such as Freiburg im Breisgau, Stuttgart, Koblenz, Berlin, Darmstadt, Frankfurt, Mannheim and Hanover. Outside of Germany, I have been to Basel, Switzerland and Milan, Italy.
To commute to lab from my Wohngemeinschaft (shared-living accomodation or apartment), I used the bus. The public transport is one of the best parts about living in Germany like many European countries as it is easily accessible, afffordable, and extensive. In fact, 50% of Germans who live in major cities don't own a car and therefore rely on public transport! Biking, especially on college campuses and schools, is very popular.